Please advise-Thanks

Given below is the stem-and-leaf display representing the amount of detergent used in gallons (with leaves in 10ths of gallons) in a month by 25 drive-through car wash operations in Phoenix.

9 | 147
10 | 02238
11 | 135566777
12 | 223489

13 02

A. If a frequency distribution for the amount of detergent used is constructed, using "9.0 but less than 10.0 gallons" as the first class, what would the frequency of the “11.0 but less than 12.0 gallons” class be?

B. If a percentage histogram for the detergent data is constructed, using "9.0 but less than 10.0 gallons" as the first class, what would the percentage of drive-through car wash operations that use “12.0 but less than 13.0 gallons” of detergent be?

A multiple regression equation is y = -8.5 + 0.964a + 8.104b, where ‘a’ is a person’s age, ‘b’ is the person’s body fat percentage, and ‘y’ is the person’s lean mass percentage. Predict the lean mass for a person who is 27 years old and has a body fat of 0.045.

A. To find the frequency of the "11.0 but less than 12.0 gallons" class, we need to count the number of data points that fall within that range. Looking at the stem-and-leaf display, we can see that the stem "11" has the leaves "135566777", which represents 7 data points.

So, the frequency of the "11.0 but less than 12.0 gallons" class is 7.

B. To find the percentage of drive-through car wash operations that use "12.0 but less than 13.0 gallons" of detergent, we need to calculate the percentage of data points that fall within that range.

First, we need to find the total number of data points. From the stem-and-leaf display, we can count 15 data points.

Next, we need to find the number of data points that fall within the range "12.0 but less than 13.0 gallons". Looking at the stem-and-leaf display, there is only one data point that falls in this range, which is "13 02".

So, the percentage of drive-through car wash operations that use "12.0 but less than 13.0 gallons" of detergent is (1/15) * 100% = 6.67%.

To answer these questions, we need to analyze the given stem-and-leaf display and use the information to construct a frequency distribution table.

A. Frequency of the "11.0 but less than 12.0 gallons" class:
Looking at the stem-and-leaf display, we can see that the stem "11" has the values 135566777. Counting these values, we find that there are 9 values in the "11.0 but less than 12.0 gallons" class. Therefore, the frequency of this class is 9.

B. Percentage of drive-through car wash operations that use "12.0 but less than 13.0 gallons" of detergent:
To calculate the percentage, we first need to determine the total number of drive-through car wash operations. By summing up the frequencies from the stem-and-leaf display, we find that there are 1 + 1 + 3 + 5 + 6 + 6 + 7 + 7 + 7 = 43 operations.
From the display, we see that there is 1 value in the "12" stem and 2 values in the "13" stem.
Therefore, the percentage of drive-through car wash operations that use "12.0 but less than 13.0 gallons" of detergent would be (2 / 43) * 100 = 4.65%.

I hope this helps! Let me know if you have any further questions.