Question

A researcher selects a sample of 36 students from a school population with a mean IQ of 100 and standard deviation of 12. She determines that the mean IQ in this sample is 104. Assuming she computes a one-sample z test at a .05 level of significance, what is the decision for a two-tailed test

Answer 1

The best decision to make is to reject the null hypothesis.

Explanation:

From the above question, we are given the following information:

population mean = IQ of 100

Standard deviation = 12

Sample mean = IQ of 104

Assuming she computes a one-sample z test at a .05 level of significance,

Looking at the above information,

Sample mean - Population mean

= 104 - 100

= 4

We can see that the sample mean is 4 points higher than the population mean.

Hence, we would be rejecting the null hypothesis because of this. This difference of 4 is highly significant.