I A rescarcher wants to eatimate the average number of children with neart discase who are between the nges of 1-5 years old. How many child: De enrolled in this study, if the researcher plans on using a 95% confidenc rants a margin of error of 0.5 and standard deviation 4?

What is the forumula for standard deviation

what is the Mean Absolute Deviation? What is it's purpose?

A researcher would like to estimate the mean amount of money that a family spends to within $75. If the amount spent by a family is considered to be normally distributed with a standard deviation of $412, what sample size would be necessary to be 93% confident?

Assuming that the heights of college women are normally distributed with a mean of 62 inches and standard deviations 3.5 inches, what percentage of woman are taller than 62 inches?

According to the Department of Education the mean number of hours college students spend studying each week follows a normal distribution with a mean of 20 hours and standard deviation of 9 hours. What ‘hours of study’ represents the 90th percentile?           What ‘hours of study’ represents the 15th percentile?

Calculate the estimated standard error for the case where the sample standard deviation is 25 and the sample size 137. Answer to three decimal places if necessary, you may round up or down.

According to the Department of Education the mean number of hours college students spend studying each week follows a normal distribution with a mean of 28 hours and standard deviation of 6 hours. What ‘hours of study’ represents the 95th percentile? What ‘hours of study’ represents the 15th percentile?

What is the z score for 20 if mean =18 and stadnard deviation =0.5