Question

1.

The mean score on the ACT test was 21.7 and the standard deviation was 5.2 . The distributions of scores was approximately bell-shaped. Compute the z-score for an ACT test score of 17 . Write only a number as your answer. Round your answer to two decimal places (for example: 3.15).

2.

A population has mean 25 and standard deviation 17 . What is the data value that has a z-score of 1 ? Write only a number as your answer.

3.

Following are the number of grams of carbohydrates in a sample of 12-ounce espresso beverages offered at Starbucks.

6, 7, 17 , 20, 22, 25, 27, 38 , 48, 59

Compute the IQR. Write only a number as your answer.

4.

Following are the playback times (in hours) for a sample of 20 MP3 players.

6 , 15, 21, 21, 23, 23, 24, 26, 27, 30, 30, 31, 41 , 51 , 61, 62, 63, 63, 64, 70

What is the 65th percentile? Write only a number as your answer. You may need to round to one decimal place.

5.

Following are the number of grams of carbohydrates in a sample of 12-ounce espresso beverages offered at Starbucks.

8 , 9, 10, 20, 22, 25, 27, 45 , 48, 56

What percentile is the beverage that has 45 grams of carbohydrates in it? Write only a number as your answer (for example, for the 23rd percentile, write 23).

Answer 1

R Code for problem 3...

x=c(6,7,17,20,22,25,27,38,48,59)
quantile(x)
y=quantile(x)
IQR=y[[4]]-y[[2]]
IQR

R Code for problem 4...

x=c(6,15,21,21,23,23,24,26,27,30,30,31,41,51,61,62,63,63,64,70)
y=quantile(x,0.65)
y