How does the IQ of people convicted of felony offenses compa

How does the IQ of people convicted of felony offenses compare with that of adults in the general population?  Suppose 9 randomly selected prisoners convicted of felony offenses had IQs as given in the table and Excel file.  Note that the IQ of adults in the general population is approximately normally distributed with mean 100.   Assume that the IQs of people convicted of felony offenses are normally distributed as well.  

a) What are the experimental units in the study?

b) What is the response variable?  Quantitative or categorical?

d) Verify the two conditions for inference based on a t distribution are met

e) Calculate the mean IQ , the standard deviation of the IQs ,and the standard deviation of the mean IQs   f) Conduct a 4step significance test to see if the mean IQ of those convicted of felony offenses is significantly different from that of the general population.  Be sure to state the conclusion in plain English, not statistics jargon.

g) Estimate the mean IQ of those convicted of felony offenses with a 95 percent confidence interval. Interpret with a statement in the context of the problem.

Table: Prisoner Number   IQ 1   100

2   135

3   108

4   94

5   111

6   96

7   99

8   104

9   116

Solution