Duplicate of Chapter 2: Density Curves & Normal Distributions

Question 1

What is the best description of this distribution's shape?

Accepted Answer

Skewed left

Question 2

For the standard Normal distribution, what approximate value is at the 72nd percentile?

Accepted Answer

0.58

Question 3

If Sally is the 3rd fastest on the track team out of 30 , at what percentile does she fall?

Accepted Answer

90th percentile

Question 4

For the old SAT math scores, μ = 470 and SD = 110. What is the z-score for a score of 500?

Accepted Answer

0.27

Question 5

About what percentage of data falls between -2 and 1 on the standard Normal distribution?

Accepted Answer

81.5 percent

Question 6

What is the interquartile range for this distribution?

Accepted Answer

6 inches

Question 7

Which of the following is NOT correct about a standard Normal distribution?

Accepted Answer

The proportion of scores z > -3.0 is 0.0013

Question 8

A distribution with a mean = 60 and SD = 6 is changed by subtracting 5 and multiplying by 1.5.

Accepted Answer

New mean = 82.5 ; New SD = 9

Question 9

Jorge's score on Exam 1 was at the 64th percentile of all students. His score falls:

Accepted Answer

between the median and the third quartile.

Question 10

A z-score of 2.3 on a Normally distributed measure corresponds to a percentile rank of:

Accepted Answer

98.93

Question 11

A distribution with a mean = 72.5 and SD = 3 is changed by adding 3.5 and dividing by 0.5.

Accepted Answer

New mean = 152 ; New SD = 6

Question 12

If the height of men is ~Normal & 99.7% are between 5 - 7 feet, what is the standard deviation?

Accepted Answer

4 inches

Question 13

For a distribution with mean = 23 & SD = 1.2, what percent of data falls between 24.2 and 25.4?

Accepted Answer

13.5

Question 14

Tina scores at 68th percentile on an exam with mean = 78 & SD = 6. What ~grade did she earn?

Accepted Answer

81

Question 15

A boy with z = -0.17 for 7 hours of sleep is from distribution with SD = 1.2 hrs. What is mean?

Accepted Answer

7.2 hours

Questions 15