Author Question: Given a normal distribution with a mean of 80 and a standard deviation of 20, an observation of x = ... (Read 18 times)

bobbysung · **on:** Jul 24, 2018

Given a normal distribution with a mean of 80 and a standard deviation of 20, an observation of x = 50 corresponds to a standard normal deviate:
a. of z = +1.5
b. of z = +3.0
c. of z = 1.5
d. of z = 3.0
e. of none of these

Question 2

If you wish to construct a confidence interval estimate for the difference between two population means, an increase in the sample sizes used will result in:
a. a decrease in the critical value z
b. a narrower confidence interval
c. a wider confidence interval
d. a confidence interval that contains zero
e. a confidence interval that does not contain zero