A random sample of n = 64 scores is obtained from a normal population with a mean of = 112 and a standard deviation of = 16. If the sample mean is M = 110, what is the z-score for the sample mean?

Note that z = (M-)/(/sqrt(n))

So for example if M= 5 and = 9 and = 2 and n = 4 then

z= (5-9)/(2/sqrt(4)) = -4/(2/2) = -4

So what is it for the question when = 112; = 16; M = 110?

A researcher is interested in whether drinking coffee influences creativity scores. The researcher knows that creativity scores are normally distributed with = 120 and = 10. What is the null hypothesis for this research study?

Note that the null hypothesis for a study is always that the population mean is the status quo. So for example if the status quo is = 100 then the null hypothesis is:

Ho: = 100

So write the null hypothesis for #2 when the status quo is = 120