In the U.S., women’s heights are normally distributed with a…

In the U.S., women’s heights are normally distributed with a mean of 63.6 inches and a standard deviation of 2.5 inches.  To become a NYC Rockette, a woman’s height must be between 66 inches and 70.5 inches.  What percent of the population of U.S. women have heights that meet the Rockette height requirement?  Answer as a percent rounded to 2 decimal places.

A child psychologist wants to determine if there is a signif…

A child psychologist wants to determine if there is a significant different between the amount of time it takes to toilet-train boys and the amount of time it takes to toilet-train girls.  The 99% confidence interval for boys was found to be 8 to 16 months.  The 99% confidence interval for girls was found to be 2 to 10 months.  With these results, is it possible  (with 99% certainty) that the mean toilet-training time for boys and girls is the same?  

The population mean number of students in an Introduction to…

The population mean number of students in an Introduction to Statistics class is 33 students with a standard deviation of 2.5 students.  In a random sample of 35 Introduction to Statistics classes, what is the probability that the mean number students is at most 34?  You can use a standard error rounded to 4 decimal places.