The terms variability, spread, and dispersion are synonyms, and refer to how spread out a distribution is. Introductory statistics lectures measures of variation descriptive statistics iii anthony tanbakuchi. In this blog post, youll learn why understanding the variability of your data is critical. Students analyze the data to make generalizations about the measures of dispersion. Using excel to calculate the measures of variability youtube. Eleventh graders investigate different measures of variability and standard deviation. Most of the scores are clustered around 3 or 4 so the median provides a better description, while the. Within the dataset the actual values usually differ from one another. Students will be able to assess the accuracy of measures of central tendency and variability in the presence of outliers. Displaying all worksheets related to statistical variability grade 6. The mean is the statistic used most often to characterize the center of the data in s.
Worksheets are grade 6 statistics and probabilty 7 weeks unit 5, grade 6 mathematics, math mammoth grade 6 b worktext sample, georgia standards of excellence curriculum frameworks, essential elements for grade 6 mathematics, mapping the world, 20 math framework grade 6, grade levelcourse. Measures of variation refer to a group of statistics that is intended to provide us with information on how a set of scores are distributed. Measures of variability are important to be familiar with when conducting research, and this quizworksheet will test your understanding of their components and. What is the best sampling technique to use for determining the average speed of the cars on a section of highway.
For example, decide whether the words in a chapter of a. Mode, median, and mean 79 mean most students will recognize the computation procedure for the mean as the process they follow to compute a simple average of test grades. These formulas are the root formulas for many of the statistical tests that will be covered later. Pdf two simple measures of variability for categorical data. Measures of variability a series of free, online video lessons with examples and solutions to help grade 7 students learn how to informally assess the degree of visual overlap of two numerical data distributions with similar variabilities, measuring the difference between the centers by expressing it as a multiple of a measure of variability. For our class data, is there more variability in student heights or student work hours. Measures of central tendency locate only the center of a distribution of measures.
Similar to measures of central tendency, there are multiple measures of variability. Variability variability serves both as a descriptive measure and as an important component of most inferential statistics. The purpose for measuring variability is to obtain an objective measure of how the scores are spread out in a distribution. This free prealgebra worksheet contains problems on measure of central tendency finding the mean, median, mode, and range for a sample set of data. Measures of variability real statistics using excel. An appropriate measure of variability to assist you in doing so is the index of qualitative variation. Measures of variability answer bailey has been playing golf on the weekends for the past three years. The distance covered by the scores in a distribution from smallest value to highest value for continuous data, real limits are used based on two scores, not all the data an imprecise, unreliable measure of variability range url for. Recently, she started keeping track of her recorded scores. Measures of variation kendall hunt higher education. We consider a random variable x and a data set s x 1, x 2, x n of size n which contains possible values of x.
Allow us to summarize our data set with a single value. To learn how to compute three measures of the variability of a data set. Students must also describe situations where one measure of central tendency might be chosen over another. Jess knows the range of any data set is the difference between the greatest and least values.
Discuss the meaning of variability calculate the different measures of variability of a given grouped data. Thus measures of variability refer to the scatter or spread of scores around their central tendency. Worksheets are measures of variability the range inter quartile range, 10 measures of variation, measures of variability, measures of central tendency variability, unit 4 statistics measures of central tendency measures, descriptive statistics measures of variability and, introductory statistics lectures. Measures of variation guided notesmeasures of variation practice pagemeasures of variation. Seventh grade lesson measures of variation range and iqr. Showing top 8 worksheets in the category measure of variability. For example, decide whether the words in a chapter of a seventhgrade science book are generally longer than the words in a chapter of a fourthgrade science book. The second group of statistics measures variation in terms of a summary measure of each scores deviation from the mean. Then explore how to describe the spread of data sets. This product includes a foldable with suggested notes, worksheet, and answer key covering comparing measures of variability 7. Students must use a password to access the problems and the time of login and logoff are automatically recorded for the teacher.
Measures of variability dispersionallow us to summarize our data set with a single value. Measure of variability worksheets teacher worksheets. Just as in the section on central tendency where we discussed measures of the center of a distribution of scores, in this chapter we will discuss measures of the variability of a distribution. Measures of average such as the median and mean represent the typical value for a dataset. Use measures of center and measures of variability for numerical data from random samples to draw informal comparative inferences about two populations. Quartiles are values that divide the data set into four equal parts. We now consider the following commonly used measures of variability of the data around the. Then, i explore the most common measures of variabilitythe range, interquartile range, variance, and standard deviation. Her supervisor asked her to keep a record of the number of sales she made each month.
Measures of central tendency are used because they represent centralized or middle values of the data. Looking specifically at range, variance, and standard deviation, this lesson explores the relationship between these measures and samples, populations, and what it says about your data. Three measures of variability the range the variance the standard deviation 7. Statistics that describe the spread or dispersion of data are called measures of variation. Comparing the measures of variability students must learn three ways to measure the variability of a distribution. Introductory statistics lectures measures of variation. Students will be able to assess the utility of outliers, specifically that they may illuminate influential factors relevant to the data set that may otherwise not have been evident. In my class, i use the left hand side of the notebook for guided notes with foldables, while the righthand side is reserved for individual practice work. Measures of dispersion although the range is easy to compute it is a crude measure of variability. Displaying all worksheets related to measures of variability.
A high school teacher at a small private school assigns trigonometry practice problems to be worked via the net. From the following example we can get a clear idea. Lesson initiator what is the purpose of finding an average. Examples and step by step solutions, how to assess the degree of visual overlap of two numerical data distributions with similar variabilities, measuring the difference between the centers by expressing it as a multiple of a measure of variability, videos, worksheets, games and activities that are suitable for common core grade 7, 7. Chapter 5 quiz chapter 5 measures of variability quiz 1. The first variability measure is obtained as one minus the square root of the sum of the squares of the relative frequencies. Her scores for june and july at her favorite 9hole par 36 golf course are provided below. An examination of measures of variation is a logical extension of any description of a data set using the measures of central tendency that we examined in the previous chapter. The measures of variability indicate how the distribution scatter above and below the central tender. Measures of variation are used to describe the distribution of the data. Measures of variability worksheets lesson worksheets. Measures of variability a high school teacher at a small private school assigns trigonometry practice problems to be worked via the net.
Analyze data science the table shows a set of scores on a room a room b 72 63 100 93 67 79 84 83 65 98 78 87 92 73 87 81 80 65 science test in two different classrooms. B applies concepts of center, spread, shape, and skewness to describe a data distribution. The following data set is a list of her sales for the last 12 months. The range is the difference between the greatest and least data values. An examination of measures of variation is a logical extension of any description of a data set using the measures of central tendency. In analyzing, statistical data, it is often useful to have numbers describe the complete set of data. Measures of variation worksheet 1 a year ago, angela began working at a computer store. In the context of inferential statistics, variability. Technically speaking, the interquartile range is a measure of association and not a measure. Consider the following two sets of data which have the same mean, 25, and the same range, 10, but obvious di erences in the pattern of variability. Pre algebra unit 9 justify measures of central tendency from measures of central tendency worksheet, source. Lets use a simple example of two classes that took the same quiz in. Grieser page 2 5 suppose the students in a class received the following test scores. Suppose you are interested in comparing the amount of variability in the variety of religious establishment in idaho and california.
Just as there are multiple measures of central tendency, there are several measures of variability. Harrison recorded the length of time, rounded to the nearest 10 min, that he spent playing video games each day for a month. Often, but not always, when comparing distributions each of these measures will give the same answer the ann e. Measures of central tendency worksheet 1 the heights in inches of eight tomato plants are. Measures of variability solutions, examples, worksheets.
Some of the worksheets displayed are measures of central tendency variability, measures of dispersion, descriptive statistics measures of variability and, chapter 3 descriptive statistics numerical measures, measures of central tendency mean median and mode examples, measures of central tendency name. Lesson 27 measures of center and variability variability read the problem below. The data set can represent either the population being studied or a sample drawn from the population. As a descriptive statistic, variability measures the degree to which the scores are spread out or clustered together in a distribution. Measures of variation notes and activities, common core standard. Introductory statistics lectures measures of variation descriptive statistics iii anthony tanbakuchi department of mathematics pima community college.
These statistics worksheets will have students use data pools and learn to calculate measures of center and the degree to which the data differs. Of these three, the standard deviation and the related measure of. The next part of this chapter presents and discusses four measures of variability. Videos and lessons with examples and solutions to help high school students learn how to use measures of center and measures of variability for numerical data from random samples to draw informal comparative inferences about two populations.
The range or difference between the first and third quartiles. A measure of variability is a summary statistic that represents the amount of dispersion in a dataset. Calculate the different measures of variability of a given grouped data. The other two measures of variability that we will consider are more elaborate and also depend on whether the data set is just a sample drawn from a much larger population or is the whole population itself that is, a census.