Question

QUESTION 13

A normally distributed population has a mean of 98.47 and a standard deviation of 0.45. Determine the sample avergage that is the third quartile for samples of size 195.

Round to the nearest hundredth

QUESTION 14

A normally distributed population has a mean of 112 and a standard deviation of 24. Determine the value of the sample average at the 25th percentile for samples of siz 140.

Round to the nearest tenth

QUESTION 15
A normally distributed population has a mean of 95 and a standard deviation of 23. Determine the value of the sample average at the 75th percentile for samples of siz 61.

Round to the nearest tenth

Answer 1

Answer 13

given that mean = 98.47, standard deviation = 0.45, sample size n = 195 and z score for third quartile or 75th percentile is 0.674 (using percentile table)

using the formula , x(bar) is the required sample mean

this implies

Answer 14

given that mean = 112, standard deviation = 24, sample size n = 140 and z score for 25th percentile is -0.674 (using percentile table)

using the formula , x(bar) is the required sample mean

this implies

Answer 15

given that mean = 95, standard deviation = 23, sample size n = 61 and z score for 75th percentile is 0.674 (using percentile table)

using the formula , x(bar) is the required sample mean

this implies