1) Although Dr. Marshall's and Dr. Benson's PSY 210 classes had the same mean Quiz 1 grade ( = 80%), Dr. Marshall's class had a standard deviation of...

1) Although Dr. Marshall's and Dr. Benson's PSY 210 classes had the same mean Quiz 1 grade (µ = 80%), Dr. Marshall's class had a standard deviation of σ = 5 and Dr. Benson's class had a standard deviation of σ = 10. 

Which class had more consistent grades?

In which class would a grade of 85% be most impressive?

A) Dr. Benson; Dr. Marshall

B) Dr. Benson; Dr. Benson

C) Dr. Marshall; Dr. Marshall

D) Dr. Marshall; Dr. Benson

2) Find the standard deviation for the following population data.

6, 4, 4, 3, 3, 2, 2, 2, 1

A) σ = 1.5

B) σ = 1.031

C) σ = 1.414

D) σ = 2

E) σ = 0.943

F) σ = 8.485

3) Find the standard deviation for the following sample data. 

X f 

8 2 

7 1 

6 4

A) s = 0.776

B) s = 1.458

C) s = 0.905

D) s = 6.194

E) s = 0.951

F) s = 0.880

G) s = 6.690

4) A sample has a standard deviation of 5. What is the variance for this sample? 

A) 5

B) 25

C) 10

D) There is not enough information to determine the sample variance.

E) 2.236