Percentiles and Normal Distribution review

Question 1

The mean of any density curve is the point

Accepted Answer

at which the curve would balance if made of solid material.

Question 2

If your score on a test is at the 60th percentile, you know that your score lies

Accepted Answer

between the median and the 3rd quartile

Question 3

Which is least likely a Normal distribution?

Accepted Answer

Family incomes of all students taking STATS 101 at State Tech.

Question 4

The distribution of heights is N(69, 2.5). What percent of men are between 66.5 & 71.5 in.?

Accepted Answer

68%

Question 5

The distribution of heights is N(69, 2.5). What percent of men are shorter than 64 inches?

Accepted Answer

2.5%

Question 6

Samir earned an 88 on a test. The class mean was 78 & std. dev. 8. His standardized score was:

Accepted Answer

1.25

Question 7

If the heights of 99.7% of men are between 60" & 84", what is the estimate of the stand. dev.?

Accepted Answer

4 inches

Question 8

The ACT is N(18,6). Wayne's standardized score is -0.7. What is his actual ACT score?

Accepted Answer

13.8

Question 9

The distribution of heights is N(69, 2.5). How tall is a man whose standardized score is 0.3?

Accepted Answer

69.75 inches

Question 10

Aman's standardized height is 0.3 & is at the 62nd percentile. What % of men are taller?

Accepted Answer

38%

Questions 10