Understanding and Comparing

DistributionsCh. 5 Day 1 NotesAP StatisticsEQ: How do we make boxplots and why? How do we compare distributions?

Examples of Boxplots

Boxplots• Title• Scale on horizontal axis• Label horizontal axis• Label the five number summary(Min, Q1,

Med, Q3, Max)• Make sure to use the modified boxplot

option on your calculator. (the one that shows outliers out to the sides)

• Are good for side to side comparison but do not show individual values

BoxplotsMake a boxplot for the test scores of 15 employees enrolled in a CPR class:

13 9 18 15 1421 7 10 11 205 18 37 16 17

Use your Calculator

What does it look like and what does this boxplot tell us about our data?

OutliersTo find outliers:1. Find the IQR2. Q1 - 1.5IQR (lower boundary)3. Q3 + 1.5IQR (upper boundary)

Anything below the lower number and above the larger number is considered an outlier.

data0 20 40 60 80 100 120

Collection 1 Box PlotDescribe the box plot below

Steps to comparing boxplots1. Identify what you are comparing

2. Show mechanics(5 # summary, IQR)3. Make a picture4. Conclusion(shape, center, spread)

Compare means to link the two data sets together in one sentence. For example, the east is more

symmetric than the west.

set_170 80 90 100 110

Collection 1 Box Plot

set_270 80 90 100 110

Collection 1 Box Plot

Compare

Which of the following distributions are more likely to

be skewed to the right than skewed to the left?

I. Household incomesII. Home pricesIII. Ages of teenage drivers

A. II only B. I and II C. I and IIID. II and III E. I, II, and III

Which of the following are true statements?A. The range of the sample data is never greater than

the standard deviation.B. The IQR is half the distance between the first

quartile and the third quartile.C. While the range is affected by outliers, the IQR is

not.

True or False.• 1. The second quartile is the median of an

ordered data set.

• 2. The five numbers you need to graph a boxplot are the minimum, the maximum, first quartile, third quartile, and the mean.

True

False

HomeworkP. 95 # 4, 7, 11, 16, 19, 21, 25

TomorrowIn Class: Ch.4 QuizHW: Ch.5 Reading Questions