For randomly selected adults, IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. A sample of 24 randomly selected college professors resulted in IQ scores having a standard deviation of 10. A psychologist is quite sure that college professors have IQ scores that have a mean greater than 100. He doesn't understand the concept of standard deviation very well and claims the standard deviation for IQ scores of college professors is equal to 15, the same standard deviation as in the general population. Use a 0.05 level of significance to test that claim. Based on the result, what do you conclude about the standard deviation of IQ scores for college professors?
Use the traditional method to test the given hypotheses. Follow the steps outlined in and draw the appropriate graph. In all cases, assume that the population is normally distributed and that the sample has been randomly selected.