Question

you are performing a study about weekly per capita milk consumption. a previous study found weekly per capita milk consumption to be normally distributed, with a mean of 45.1 fluid ounces and a standard deviation of 8.8 fluid ounces. you randomly sample 30 people and record the weekly milk consumptions shown below. 38 55 33 39 44 49 30 64 37 48 41 23 39 54 45 41 41 50 48 47 36 29 23 41 61 42 50 46 53 39 (a) draw a frequency histogram to display these data. use seven classes. choose the correct answer below.

Explanation:

Step1: Find class width

The minimum value in the data set is 23 and the maximum is 64. The range is $64 - 23=41$. With 7 classes, the class - width $w=\frac{41}{7}\approx6$. We can use a class - width of 6.

Step2: Define class intervals

The first class can start at 23. The class intervals are: 23 - 28, 29 - 34, 35 - 40, 41 - 46, 47 - 52, 53 - 58, 59 - 64.

Step3: Count frequencies

For the class 23 - 28: There are 2 values (23, 23).
For the class 29 - 34: There are 2 values (30, 33).
For the class 35 - 40: There are 8 values (36, 37, 38, 39, 39, 39, 39, 39).
For the class 41 - 46: There are 9 values (41, 41, 41, 41, 41, 42, 44, 45, 46).
For the class 47 - 52: There are 5 values (47, 48, 48, 49, 50).
For the class 53 - 58: There are 3 values (53, 54, 55).
For the class 59 - 64: There are 1 value (61, 64).

Step4: Match with histograms

By comparing the frequencies of each class with the histograms given, we can determine the correct one.

Answer:

A.