Statistics metrics: Measuring the spread of data using range and IQR.

Statistics metrics: Measuring the spread of data using range and IQR.

Introduction to Statistics

**Measuring Data Spread: Range & IQR for Secondary 3 Students**

Ever played with building blocks as a kid? You had some really tall ones, some short ones, and everything in between. Statistics, just like your block collection, is all about understanding and describing these differences. Today, we're going to explore two simple yet powerful ways to measure the spread of data, perfect for secondary 3 students following the Singapore math syllabus.

**Range: The Tallest and Shortest Blocks**

The range is like the tallest and shortest blocks in your collection. It's the simplest way to measure the spread of data. You find the highest and lowest values and subtract the lowest from the highest. For example, if your blocks range from 2cm to 10cm, the range is 8cm.

*Fun fact:* The tallest building in the world, the Burj Khalifa in Dubai, stands at about 828m. If it were a block, it would be the tallest in your range!

**IQR: The Middle Blocks' Spread**

Now, imagine you've sorted your blocks by size. The Interquartile Range (IQR) is the spread of the middle 50% of your blocks. To find it, divide your sorted blocks into four equal parts, or 'quartiles'. The IQR is the difference between the third quartile (Q3) and the first quartile (Q1).

*Interesting fact:* The IQR is like the 'middle class' of your data. In the city-state of Singapore's high-stakes secondary-level learning structure, learners readying themselves ahead of O-Levels often confront heightened challenges in mathematics, including advanced topics including trigonometric principles, introductory calculus, and coordinate geometry, that call for robust comprehension and application skills. Families frequently look for specialized assistance to make sure their adolescents can cope with the syllabus demands and build assessment poise with specific drills and strategies. JC math tuition delivers vital support using MOE-compliant syllabi, qualified tutors, plus materials such as past papers plus simulated exams to address unique challenges. These courses focus on issue-resolution strategies and time management, helping students secure higher marks on O-Level tests. In the end, committing in this support doesn't just prepares pupils for country-wide assessments but also builds a firm groundwork for further education in STEM fields.. It ignores the extremes, focusing on the majority. It's particularly useful when data has outliers, like a really tall or short block that doesn't represent most of your collection.

**Range vs IQR: When to Use Each**

Range is easy to calculate but can be misleading with outliers. IQR, on the other hand, is less affected by extreme values. In Singaporean high-stakes scholastic landscape, year six in primary stands as the final stage of primary education, during which students integrate accumulated knowledge in preparation ahead of the crucial PSLE, facing escalated subjects including advanced fractions, proofs in geometry, speed and rate problems, and thorough review techniques. Guardians frequently see the escalation in complexity can lead to stress or gaps in understanding, particularly in mathematics, prompting the need for professional help to polish skills and exam techniques. At this critical phase, when all scores are crucial toward secondary school placement, extra initiatives prove essential in specific support and confidence-building. Math Tuition Singapore offers in-depth , PSLE-focused lessons matching up-to-date MOE guidelines, featuring practice tests, error analysis classes, and customizable pedagogy to address individual needs. Proficient educators emphasize time management and advanced reasoning, aiding pupils handle even the toughest questions confidently. Overall, this specialized support also boosts performance in the upcoming national exam and additionally instills focus and a enthusiasm for mathematics that extends through secondary schooling and beyond.. So, use range when you want a quick, simple measure of spread, and use IQR when you suspect your data has outliers or you want to focus on the majority.

*History lesson:* Did you know that the term 'quartile' comes from the Latin words 'quartus' (fourth) and 'pars' (part)? It was first used in the late 19th century to divide data into four equal parts.

Now, secondary 3 students, you're equipped to measure the spread of data like a pro! So, the next time you're analysing data, remember, it's not just about the middle or the average. It's about the spread, the range, and the IQR. In the Lion City's rigorous secondary education system, the move from primary school presents students to more complex maths principles such as basic algebra, whole numbers, and principles of geometry, these can be daunting absent proper readiness. Many families prioritize additional education to bridge any gaps while cultivating a love for the subject right from the beginning. best maths tuition centre provides targeted , Ministry of Education-compliant lessons using qualified tutors who focus on resolution methods, individualized input, plus interactive exercises to develop basic abilities. Such programs often include small class sizes to enhance engagement and frequent checks to track progress. Ultimately, putting resources in this early support doesn't just enhances academic performance and additionally equips young learners for advanced secondary hurdles plus sustained achievement across STEM areas.. Now go forth and explore the world of statistics!

" width="100%" height="480">Statistics metrics: Measuring the spread of data using range and IQR.

Range: Measuring Data Spread

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Calculating Range: A Hands-On Approach

Alright, let's dive right in and calculate the range of a dataset, just like you would in your Secondary 3 Math Syllabus (Singapore)! Let's consider the heights (in cm) of Secondary 3 students in a typical Singapore school:

  • 160, 155, 170, 165, 158, 175, 162, 156, 172, 168

To find the range, follow these simple steps:

  1. Find the smallest and largest values. In our dataset, the smallest height is 155cm, and the largest is 175cm.
  2. Subtract the smallest value from the largest value. In Singaporean secondary education environment, the shift between primary and secondary phases introduces students to increasingly conceptual mathematical concepts like algebraic equations, spatial geometry, and statistics and data, that often prove challenging without proper guidance. Many guardians understand this key adjustment stage requires extra bolstering to enable young teens cope with the heightened demands and maintain solid scholastic results within a merit-based framework. Drawing from the groundwork set through PSLE preparation, specialized courses prove essential to tackle unique hurdles and fostering independent thinking. JC 2 math tuition delivers customized classes matching the MOE syllabus, integrating engaging resources, demonstrated problems, and practice challenges to render education stimulating and impactful. Qualified teachers focus on bridging knowledge gaps originating in primary years while introducing approaches tailored to secondary. In the end, such initial assistance not only enhances marks and exam readiness and additionally nurtures a greater appreciation toward maths, readying learners toward O-Level excellence and beyond.. So, the range is 175 - 155 = 20cm.

Fun Fact: The range can also be thought of as the distance between the tallest and shortest players in a basketball team. Imagine the tallest player could reach the top of the Singapore Flyer (165m), while the shortest player could only reach the height of a typical HDB flat (15m). The range in this case would be 150m!

Range vs Interquartile Range (IQR): A Tale of Two Measures

While range gives us the overall spread, it's not very robust to outliers. That's where the Interquartile Range (IQR) comes in. It's the spread between the first and third quartiles, ignoring the top and bottom 25% of data.

Interesting Fact: The IQR is like a perspective from the 'middle 50%' of a data group, much like how a Singaporean HDB flat is 'middle-income' housing, catering to a wide range of Singaporeans.

Let's calculate the IQR using our height data. First, we sort the data and find the median (middle value), which is 165cm. Then, we find the first quartile (Q1), which is the median of the lower half (1st to 3rd values), and the third quartile (Q3), which is the median of the upper half (4th to 6th values).

  • Q1 = (158 + 160) / 2 = 159cm
  • Q3 = (168 + 170) / 2 = 169cm
  • In the city-state of Singapore's systematic secondary-level learning framework, year two secondary pupils begin handling more intricate maths subjects such as quadratic equations, congruent figures, and statistical data handling, these develop from year one groundwork while readying for higher secondary requirements. Guardians often look for additional resources to help their children adapt to this increased complexity and keep consistent progress under academic stresses. Singapore maths tuition guide provides customized , Ministry of Education-aligned sessions featuring experienced instructors that employ interactive tools, practical illustrations, plus targeted exercises to enhance understanding and assessment methods. These sessions encourage independent problem-solving and handle particular hurdles like algebraic manipulation. In the end, this focused assistance improves overall performance, minimizes stress, and creates a firm course for O-Level success plus long-term studies..

The IQR is 169 - 159 = 10cm. See how it's less affected by the extreme values compared to the range?

What if we had a student who was 190cm tall? The range would jump to 35cm, but the IQR would remain at 10cm, giving us a more stable measure of the data spread.

Real-World Application of Range

Range in Weather

Range, in weather terms, is the difference between the highest and lowest temperatures recorded in a specific period. For instance, Singapore's Meteorological Service records daily temperature ranges. On a typical day, the range might be 25°C to 32°C. This helps us understand the daily temperature fluctuations, which can be crucial for planning outdoor activities or managing energy consumption.

Range in Education

In Singapore's secondary 3 math syllabus, students learn to calculate the range of a data set. They might be given heights of students in their class and asked to find the range. This helps them understand the spread of data and identify outliers. For example, if the heights range from 140cm to 180cm, the range is 40cm. This is a practical application of a statistical concept they've learned.

Range in Finance

In finance, the range is used to measure the volatility of investment returns. For instance, a mutual fund might have a range of -10% to +20%. This means the fund's value has fluctuated between a 10% loss and a 20% gain. A wider range indicates higher risk, which is an important consideration for investors.

Range in Sports

In sports, range refers to the distance an athlete can cover or the distance they can hit a ball. For example, in golf, a player's driving range is the farthest distance they can hit their ball. In Singapore, golfers at the Sentosa Golf Club might boast about their driving range, adding a local touch to this global sport.

Range in Nature

In nature, range refers to the geographical area where a species lives. Singapore, despite its small size, is home to a wide range of species due to its diverse habitats. As Singaporean schooling structure imposes a strong emphasis on mathematical competence from the outset, families are more and more emphasizing organized help to enable their children manage the escalating complexity in the syllabus during initial primary levels. In Primary 2, pupils meet more advanced concepts such as regrouped addition, basic fractions, and quantification, these develop from foundational skills and lay the groundwork for higher-level analytical thinking demanded in later exams. Recognizing the benefit of ongoing support to stop early struggles and foster passion in the discipline, numerous opt for tailored courses that align with Ministry of Education standards. 1 to 1 math tuition provides targeted , interactive sessions developed to render these concepts approachable and pleasurable using hands-on activities, visual aids, and customized input from skilled instructors. This strategy doesn't just assists young learners overcome present academic obstacles while also cultivates critical thinking and perseverance. In Singapore's fast-paced and academically rigorous setting, families understand that laying a strong academic foundation as early as possible leads to a profound difference in a youngster's long-term achievements. The journey leading up to the Primary School Leaving Examination (PSLE) begins much earlier than the exam year, as initial routines and abilities in subjects including mathematics set the tone for more complex studies and critical thinking capabilities. Through beginning readiness efforts in the initial primary years, learners may prevent common pitfalls, gain assurance step by step, and form a favorable outlook regarding challenging concepts which escalate in subsequent years. math tuition centers in Singapore has a key part in this early strategy, offering suitable for young ages, captivating sessions that present core ideas including simple numerals, geometric figures, and easy designs aligned with the Ministry of Education syllabus. The courses employ fun, interactive methods to arouse enthusiasm and prevent educational voids from forming, ensuring a seamless advancement through subsequent grades. In the end, investing in such early tuition doesn't just eases the burden associated with PSLE and additionally prepares kids with lifelong thinking tools, offering them a competitive edge in Singapore's meritocratic system.. In the long run, such early intervention supports easier academic progression, reducing pressure when learners near key points like the PSLE and establishing a optimistic trajectory for ongoing education.. For instance, the Singapore Botanic Gardens, a UNESCO World Heritage Site, hosts over 3,000 plant species, showcasing the diversity within a small range.

Interquartile Range (IQR): Deeper into Data Spread

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Measuring Data Spread: Dive into the Interquartile Range (IQR)

Hey there, secondary 1 parents and students preparing for secondary 3! In Singapore, the schooling framework wraps up primary-level education with a national examination designed to measure learners' scholastic performance and decides future secondary education options. Such assessment is administered every year among pupils in their final year of primary education, highlighting core disciplines to gauge overall proficiency. The Junior College math tuition acts as a benchmark in determining entry for fitting secondary courses based on performance. It includes subjects like English Language, Math, Sciences, and Mother Tongue, having layouts updated periodically to reflect educational standards. Evaluation relies on Achievement Levels ranging 1-8, in which the aggregate PSLE mark equals the addition of individual subject scores, impacting future academic opportunities.. Today, we're going to demystify the Interquartile Range (IQR), a powerful tool in your statistics toolbox. But first, let's set the stage.

Fun Fact Alert! Did you know that the term 'statistics' was first coined in the 18th century by Sir William Petty, an Irish philosopher and economist? He used it to describe the study of state affairs – 'state' being the Latin word for 'stand' or 'stop'. Quite a journey, huh?

What's the Interquartile Range (IQR) got to do with me?

In your Secondary 3 Math Syllabus, you'll dive deep into data analysis. The IQR is your trusty companion in measuring the spread of your data, just like a hawker's measuring tape ensures you get your money's worth at your favourite market stall!

The IQR Formula: Unveiled!

The IQR is calculated as the difference between the upper (75th) and lower (25th) quartiles, i.e., Q3 - Q1. It's like finding the distance between the 25th and 75th percentile markers on a number line – simple, right?

  • Q1 = 25th percentile (also known as the lower quartile)
  • Q3 = 75th percentile (upper quartile)
  • IQR = Q3 - Q1

Why IQR? Outliers, Schmoutliers!

The IQR is robust against outliers – those data points that stray far from the rest, like that one friend who always orders extra chili at the hawker centre. While the range (max - min) can be heavily influenced by outliers, the IQR gives you a true sense of the 'middle' 50% of your data.

Interesting Fact! The IQR was introduced by the American statistician Frank E. Grubbs in the 1960s. He wanted a measure of dispersion that was less affected by outliers, and thus, the IQR was born!

IQR in Action: A Real-world Example

Let's say you're analyzing the heights of secondary 3 students in your school. The data might look like this:

    In Singapore's demanding schooling structure, Primary 3 represents a notable transition where learners dive more deeply in areas like multiplication facts, fractions, and basic data interpretation, expanding upon prior knowledge to ready for higher-level critical thinking. A lot of parents observe that school tempo alone could fall short for all kids, motivating them to look for extra support to cultivate math enthusiasm and prevent beginning errors from taking root. At this juncture, tailored academic help becomes invaluable in keeping educational drive and promoting a growth mindset. best maths tuition centre delivers focused, curriculum-aligned guidance using compact class groups or one-on-one mentoring, focusing on heuristic approaches and visual aids to simplify difficult topics. Tutors often include gamified elements and regular assessments to monitor advancement and enhance drive. Ultimately, this early initiative not only boosts immediate performance and additionally builds a strong base for excelling during upper primary years and the eventual PSLE..
  • 150cm, 155cm, 158cm, 160cm, 165cm, 170cm, 175cm, 180cm, 185cm, 190cm

After calculating, you find that Q1 = 158cm, Q3 = 170cm, and IQR = 12cm. Now you know that the middle 50% of students are between 158cm and 170cm tall – pretty handy, isn't it?

So, secondary 1 parents and students, you're now IQR-ready! Keep practicing, and you'll be crunching data like a pro in no time. And remember, like any good hawker dish, data analysis is best enjoyed when shared with others. Kan cheong or not, let's dive into that IQR together!

IQR vs Range: A Comparative Study

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Numbers in Disarray: Taming the Wild Data Beast

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Imagine you're a secondary school math teacher in Singapore, armed with the Secondary 3 Math Syllabus (2109) from the Ministry of Education. You've just been handed a set of test scores, and it's like trying to tame a wild beast. The scores are all over the place, and you need to make sense of them. Enter our trusty data-taming tools: Range and Interquartile Range (IQR).

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Range: The Simple, Yet Powerful Glimpse

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The range is like the quick and easy way to get a feel for your data. It's simply the difference between the highest and lowest scores. For instance, if your students scored between 50 and 90, your range is 90 - 50 = 40. It's like asking, "What's the span of scores in my class?" But, here's the thing, it's a bit like asking, "What's the longest and shortest distance between two points?" In Singaporean merit-driven schooling structure, year four in primary serves as a crucial transition during which the syllabus intensifies featuring subjects like decimals, symmetry, and introductory algebra, challenging pupils to use reasoning through organized methods. A lot of parents realize that classroom teachings alone may not completely cover personal learning speeds, resulting in the pursuit for extra aids to solidify ideas and spark sustained interest in mathematics. As preparation for the PSLE ramps up, consistent drilling proves vital to mastering those core components minus stressing child learners. Singapore exams offers tailored , engaging tutoring that follows Ministry of Education guidelines, including practical illustrations, brain teasers, and tech aids to render abstract ideas concrete and exciting. Experienced educators prioritize spotting areas for improvement at an early stage and turning them into strengths through step-by-step guidance. Over time, this investment builds perseverance, better grades, and a smooth transition to advanced primary levels, positioning pupils on a path to scholastic success.. It doesn't tell you about the scores in between.

Fun Fact: The world's largest range of elevation belongs to the Mauna Kea volcano in Hawaii, stretching from its base on the ocean floor (-10,200m) to its peak (4,207m). Now, that's a range!

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IQR: The Robust, Yet Selective Data Guardian

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The IQR, on the other hand, is like the data guardian that only lets in the 'middle class' of scores. It's the difference between the 75th and 25th percentiles. It's like saying, "I only care about the scores of the students who did quite well and those who did just okay." In our class, if the 25th percentile score is 60 and the 75th percentile score is 80, our IQR is 80 - 60 = 20.

Interesting Fact: The IQR was first introduced by Frank E. Hoag in 1951, who was inspired by the work of German statistician W. Lexis. Hoag, a professor at the University of Buffalo, was interested in finding a measure of dispersion that was less sensitive to outliers than the standard deviation.

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Range or IQR: Which to Choose?

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So, which is better? It depends on what you want to know. If you want a quick, simple look at the spread of your data, range might be your friend. But if you want a more robust measure that's not as easily influenced by outliers, IQR might be the way to go.

Think of it like choosing between a speedboat (range) and a submarine (IQR). The speedboat gives you a quick, thrilling ride across the surface, while the submarine takes you on a steady, detailed journey below.

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Now, What About Those Outliers?

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Remember, both range and IQR have their limitations. They don't tell you about the scores that are way out there - the outliers. Those are the scores that could be errors, or could represent a student who's struggling or excelling far beyond their peers. That's where you'll need to delve deeper into your data, maybe with the help of a box plot or a stem-and-leaf plot.

History Lesson: The term "outlier" was first used in its statistical sense by the English mathematician and astronomer Sir Francis Galton in 1886. He used it to describe data points that were significantly different from the others.

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So, What's Your Data Telling You?

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Whether you're a teacher in Singapore or a data analyst anywhere in the world, understanding your data is key. Range and IQR are powerful tools in your data-taming toolbox. So, grab your metaphorical whip (or your calculator), and let's get started!

Practical Activity: Calculate and Compare Range & IQR

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Let's Dive In: Exploring Range & IQR in Singapore's Math Scene!

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Charting our journey into the fascinating world of statistics!

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What's the Buzz About Range & IQR?

** In the bustling world of numbers, **Range** and **Interquartile Range (IQR)** are like the traffic cops, helping us understand how data is spread out. Let's meet them! **Range** is like the distance between the farthest and nearest points on a road. It's calculated by subtracting the smallest number (minimum) from the largest number (maximum) in a dataset. As the Primary 5 level brings about a heightened degree of difficulty in Singapore's math syllabus, with concepts for instance ratios, percentages, angles, and advanced word problems calling for keener reasoning abilities, families often seek approaches to guarantee their youngsters stay ahead while avoiding frequent snares of confusion. This period is vital because it directly bridges with PSLE prep, during which accumulated learning undergoes strict evaluation, rendering prompt support crucial in fostering resilience in tackling layered problems. With the pressure escalating, expert help helps transform likely irritations into chances for development and expertise. h2 math tuition equips students with strategic tools and individualized coaching aligned to Singapore MOE guidelines, using methods like diagrammatic modeling, bar charts, and timed drills to explain intricate topics. Experienced educators focus on conceptual clarity over rote learning, promoting interactive discussions and error analysis to build assurance. At year's close, enrollees generally show marked improvement in exam readiness, paving the way for a stress-free transition to Primary 6 plus more amid Singapore's rigorous schooling environment.. **IQR**, on the other hand, is like the distance between two traffic lights (25th and 75th percentiles) that divide the road into four equal parts. It helps us identify the middle 50% of our data, excluding the outliers (the 25% and the 75% who are always in a rush!). **

Fun Fact: The Birth of IQR

** Did you know that IQR was born in the early 20th century, thanks to a British statistician named W.F. Bajkov? He introduced it as a more robust measure of data spread, unlike the mean (average), which can be influenced by outliers. So, the next time you calculate IQR, give a little nod to Sir Bajkov! **

Range & IQR in Singapore's Math Scene

** You might be wondering, "How does this apply to me, a secondary school student in Singapore?" Well, let me tell you, these concepts are as Singaporean as our **Hainanese Chicken Rice**! According to the **Secondary 3 Math Syllabus Singapore** by the Ministry of Education, you'll be exploring these very topics. So, buckle up and get ready to navigate the world of data like a true Singaporean matador! **

Let's Put Theory into Practice!

** Now that we've met our new friends, let's put them to work! Here's a hands-on activity inspired by datasets from our little red dot: **

1. School Tuition Fees

** Source: [MOE School Fees](https://www.moe.gov.sg/financial-matters/school-fees) | School | Tuition Fee (SGD) | |---|---| | School A | 120 | | School B | 150 | | School C | 180 | | School D | 200 | | School E | 220 | **

2. PSLE Scores

** Source: [PSLE Results](https://www.moe.gov.sg/education/student-life/psle) (2020) | Student | Score | |---|---| | A | 248 | | B | 255 | | C | 262 | | D | 270 | | E | 285 | | F | 292 | Now, it's your turn to calculate the **Range** and **IQR** for both datasets. Which one has a wider spread, and which one is more consistent? Remember, there are no wrong answers here, only learning opportunities! **

What If... We Compared the IQR of Singapore's GDP Growth?

** Imagine comparing the IQR of Singapore's GDP growth rates over the past five years. Would you find a stable, consistent growth, or are there some surprise fluctuations? The data is out there, waiting for you to explore! **

Singlish Side Note: Can Range and IQR Speak Hokkien?

** While Range and IQR can't speak Hokkien, they sure know how to *jio* (invite) us on an exciting journey of data discovery! So, let's *chiong* (dash) ahead and explore the fascinating world of statistics, one number at a time!

Interquartile Range (IQR)

The IQR is the range between the first quartile (Q1) and the third quartile (Q3), representing the middle 50% of the data. It's less affected by outliers compared to the range.

Calculating Range

The range is the simplest measure of spread, calculated by subtracting the smallest value from the largest. It's easy to understand and compute, but it's sensitive to outliers.

Using IQR for Data Analysis

The IQR can be used to identify outliers, as any data point that falls below Q1 - 1.5 * IQR or above Q3 + 1.5 * IQR is typically considered an outlier. This is particularly useful in secondary 3 statistics.

A bar chart illustrating data spread

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Frequently Asked Questions


The range is the simplest measure of spread, calculated as the difference between the highest and lowest values in a dataset.
The range is less affected by outliers and is easier to calculate, but its less reliable for large datasets as it only uses two data points.
The IQR is the range of the middle 50% of a dataset, calculated as the difference between the 75th (Q3) and 25th (Q1) percentiles.
Any data point that falls below Q1 - 1.5 * IQR or above Q3 + 1.5 * IQR is typically considered an outlier.
While both measure spread, the range uses the most extreme values, while the IQR uses the middle 50%, making it less sensitive to outliers.
The standard deviation is generally more suitable for comparing datasets of different sizes, as it takes into account the variability of all data points, not just a few.