bradley ENC510 Quiz 3.1- z-Scores

Question 1 of 10

10.0/ 10.0 Points

The average man in an industrialized country lives µ = 70 and ? = 6.3. What percentage of men live 75 years or longer?

•

A. 29%

•

B. 21%

•

C. 25%

•

D. 79%

Question 2 of 10

10.0/ 10.0 Points

The average man in an industrialized country lives µ = 70 and ? = 6.3. What percentage of men live between 65 and 75 years?

•

A. 29%

•

B. 44%

•

C. 57%

•

D. 22%

Question 3 of 10

10.0/ 10.0 Points

The scores on a statewide chemistry exam were normally distributed with ?=73.08 and ?=6. Gabriela scored 78 on the exam. Gabriela's exam grade was higher than what percentage of test-takers?

•

A. 79%

•

B. 85%

•

C. 29%

•

D. 21%

Question 4 of 10

10.0/ 10.0 Points

The scores on a statewide math exam were normally distributed with ?=74 and ?=8.

What proportion of test-takers had a grade between 66 and 88 on the exam?

•

A. 10%

•

B. 80%

•

C. 34%

•

D. 40%

Question 5 of 10

10.0/ 10.0 Points

A group of students decide to participate in a national strength test. Assume a normal distribution and the following population parameters for the test:

m=580 s2 = 72.25

What percent students would you expect to get a below 70?

•

A. 90%

•

B. 50%

•

C. 0

•

D. 100%

Question 6 of 10

10.0/ 10.0 Points

In a population of ages where the mean age is 45 and the standard deviation is 5.25, what are the ages of the youngest 7% and the oldest 12%?

Younger than _______ Older than _______

•

A. 37 and 51

•

B. 40 and 50

•

C. 52 and 27

•

D. 33 and 77

Question 7 of 10

0.0/ 10.0 Points

In a normal distribution of pain estimates (0 = no pain, 100 = lots of pain) where m = 25 and s = 3, what percent would you expect to estimate their pain to be above a 32?

•

A. 24%

•

B. 1%

•

C. 49%

•

D. 5%

Question 8 of 10

10.0/ 10.0 Points

Consider a normal distribution with a mean of 86 and a variance of 16. What percentage of scores are above 78?

•

A. 2%

•

B. 47%

•

C. 98%

•

D. 66%

Question 9 of 10

10.0/ 10.0 Points

A normal distribution has a mean of 10 and a standard deviation of 10. What is the number such that 21% of the observations lie below it?

•

A. 10

•

B. 2

•

C. 18

•

D. 12

Question 10 of 10

10.0/ 10.0 Points

In a normal distribution with mean 3 and variance 49, what are the upper and lower limit scores for the middle 40% of the data?

•

A. -1 and -7

•

B. 1 and 7

•

C. -1 and 7

•

D. -7 and 1