Homework 7

You learn the average GRE score of private college graduates pursuing their MPH is

1500 with a standard deviation of 100. You want to determine whether CSU

Students are equally prepared. You randomly select 100 GRE scores of CSU

Graduates and find that the mean is 1545. Do a hypothesis test to see if this

Difference is of any real significance atα=.05.Apply and show all six steps.

µ=1500, =100, n=100, sample mean=1545, α=0.05


Null hypothesis: µ=1500

Alternative hypothesis: µ1500

Starndard error=



Z=sample mean – pop. Mean/ standard error

=1545- (1500/10)


Zα = 0.96

Since Z>Zα, then we reject the null hypothesis at 0.05 level of significance

Conclusion: There is significant difference from the population mean; mean is not 1500