Question

1-

Find the z-score for which 70% of the distribution's area lies to its right.

A. - 0.98

B. - 0.47

C. - 0.81

D. - 0.53

2-

Find the z-scores for which 98% of the distribution's area lies between - z and z.

A. (- 2.33,2.33)

B.( - 1.645,1.645)

C.( - 0.99,0.99)

D.(- 1.96,1.96)

3- Assume that the heights of women are normally distributed with a mean of 62.4 inches and a standard deviation of 2.5 inches. Find Q 3, the third quartile that separates the bottom 75% from the top 25%.

A. 60.7

B. 65.6

C. 65.3

D.64.1

Answer 1

To find the Z score we use the Z table shown below

a) Z for the point that separates top 70% is

Z=-0.53

b) The Z scores within the 98 % of data lies is

A. (- 2.33,2.33)

c) Since the third quartile separates the bottom 75 % hence Z score is

Z=0.68 now by Z formula