Heather has a bag with 3 marbles, 7 tennis balls, 3 apples, and 3 books. What is the ratio of books to tennis balls? A.
(3/7) or 3:7
B.
(7/8) or 7:8
C.
(4/7) or 4:7

B

Step-by-step explanation:

I hope it's correct and I'm thinking it is,. Sorry if it's not

I think A

Step-by-step explanation:

3/7. Or 3:7

Cause there are 3 books and 7 tennis balls

---- sample standard deviation

---- sample variance

Step-by-step explanation:

Solving (a): The sample variance

First, we calculate the midpoint of each class (this is the average of the limits)

So, we have:

And so on

So, the table becomes:

Calculate the mean

The variance is:

So, we have:

The sample standard deviation is:

Solving (b): The sample variance

In (a), we calculate the sample variance to be: