Suppose the mtcars data set has 31 records (e.g., 30 degrees of freedom).

How large would the test statistic have to be (e.g., critical value) to reject the null hypothesis (Ho) for a two sided test with P=0.05?

How large would the test statistic have to be (e.g., critical value) to reject the null hypothesis (Ho) for a one sided test with P=0.05?

What would be the critical values for the Framingham Heart Study data? Why are the numbers smaller?