Warm-up2.3 Measures of Center and Spread

N Min Q1 Median Q3 MaxNo Caffeine

15 16 20 21 24 26

Low Caffeine

15 16 18 21 24 27

High Caffeine

15 12 17 19 22 24

a) Describe the W’s for these data: Who, what, when, where, why, and how.b) Name the variables and classify each as categorical or quantitative.c) Create parallel boxplots to display these results as best you can with this information.d) Write a few sentences comparing the performances of the three groups.

Student of the day!Block 1

Student of the day!Block 2

Homework Answers2.2 E #21 a and b.

E#21 c and d

E# 22 a - c

2.3 Measures of Center and Spread So far we are have learned how to create the following data displays:Histograms, Stem-and-leaf plot, Boxplot, and Dotplot

Today we will also learn how to make a relative frequency histogramAND a modified boxplot.

This bar chart shows a distribution of the number of children in a sample of 1000 randomly selected families in the United States. Makethe necessary changes to convert it to a relative frequency bar chart

Modified Boxplot5 number summary

Standard Deviations and Frequency

Mean: Mean w/ Frequency:

Standard Deviation: Standard Deviation with Frequency:

n

xi

n

fxi )(

1

)( 2

n

xxs i

1

)( 2

n

fxxs i

Remaining 2.3 Notes• Complete the remaining 2.3 Notes on Investigating

the difference between recentering and rescaling• After about 15 minutes we will go over what you

should have learned.• If you finish early start on the homework.• 2.3 pg 63 D #16 answer all parts; read 2.4

Recentering and Rescaling Discovery Sheet• Recentering and rescaling data are important ideas in

A.P. Statistics.• You should know how adding n to each of the numbers in

a data set affects the mean and measures of spread.• You should know how multiplying each of the numbers

by n affects the mean and measures of spread.