Find the z-score for which 5% of the distribution\'s area lies between -z and z.

Question

Find the z-score for which 5% of the distribution's area lies between -z and z. Find the z-score for which 12% of the distribution's area lies between -z and z. In Exercises 31-38, answer the questions about the specified normal distribution. In a survey of women in the United States (ages 20-29), the mean height was 64.2 inches with a standard deviation of 2.9 inches. (a) What height represents the 95th percentile? (b) What height represents the first quartile? In a survey of men in the United Slates(ages 20-29), the mean height was 69.4 inches with a standard deviation of 2.9 inches. (a) What height represents the 90th percentile? (b) What height represents the first quartile? The time spent (in days) waiting for a heart transplant for people ages 35-49 can be approximated by a normal distribution, as shown in the figure. (a) What waiting time represents the 5th percentile? (b) What waiting time represents the third quartile? The time spent (in days) waiting for a kidney transplant for people ages 35-49 can be approximated by a normal distribution, as shown in the figure. (a) What wailing time represents the 80th percentile? (b) What waiting time represents the first quartile? The average time spent sleeping (in hours) for a group of medical residents at a hospital can be approximated by a normal distribution, as shown in the figure.

Explanation / Answer

32)for 90th percentile z=1.2816

a)hence corresponding value =mean +z*std deviation =73.1165

b)for first quartile z=-0.6745

hence corresponding value =mean +z*std deviation =67.4440

34) for 80th percentile; z=0.8416

hence corresponding value =mean +z*std deviation =1852.845

b)for first quartile ' z=-0.6745

hence corresponding value =mean +z*std deviation =1530.671

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