What Makes the Standard Deviation Larger or Smaller?

You will find 15 pairs of graphs on the next several pages.  The mean for each graph (m) is given just above each histogram.  For each pair of graphs presented below

1.   Indicate whether one of the graphs has a larger standard deviation than the other or if the two graphs have the same standard deviation. 

2.   Try to identify the characteristics of the graphs that make the standard deviation larger or smaller.

You can check your answers against the instructor’s answer key as you complete each item or  page.

                 

1.

A            m = 2.57                     B               m = 3.33

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

2.

A             m = 2.33                    B               m = 3.33

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

3.

A               m =  .33                   B               m =  4.33

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

4.

A                m = 2.50                 B               m = 2.56

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

5.

A                  m = 2.50               B               m =2.50

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

6.

A                m = 2.50                 B               m = 2.50

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

7.

A                  m = 2.00               B               m = 2.00

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

8.

A                   m = 1.93              B               m = 2.00

A has a larger standard deviation than B

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

9.

A                   m = 1.93              B               m = 2.00

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

10.

A                  m = 5.43               B               m = 5.86

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

11.

A                  m = 5.43               B               m = 5.57

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

12.

A                  m = 5.33               B               m = 5.48

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

13.

A                   m = 8.33                 B              m = 5.00

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

14.

A                   m = 6.15                 B              m = 3.38

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

15.

A                   m = 5.86                 B              m = 3.38

A has a larger standard deviation than B

 

B has a larger standard deviation than A

Both graphs have the same standard deviation

 

 

Answers to the items:

 

ITEM

sd of Graph A

sd of Graph B

Correct Decision

 

1

s = 1.365

s = 1.491

B is larger

2

s = .471

s = .943

B is larger

3

s = .471

s = .471

SAME

4

s = 1.708

s = 1.012

A is larger

5

s = 1.708

s = 2.50

B is larger

6

s = 1.803

s = 1.708

A is larger

7

s = 1.00

s = 1.686

B is larger

8

s = 1.280

s = 1.686

B is larger

9

s = 1.280

s = 1.00

A is larger

10

s = 1.400

s = 2.799

B is larger

11

s = 1.400

s = 1.400

SAME

12

s = 1.743

s = 1.332

A is larger

13

s = 1.743

s = 2.415

B is larger

14

s = 2.646

s = 2.075

A is larger

15

s = 3.126

s = 2.075

A is larger