Men versus women The National Assessment of Educational Progress (NAEP) Young Adult Literacy Assessment Survey interviewed a random sample of 1917 people 21 to 25 years old. The sample contained 840 men and 1077 women.49 The mean and standard deviation of scores on the NAEP's test of quantitative skills were = 272.40 and si = 59.2 for the men in the sample. For the women, the results were 2 = 274.73 and s2 = 57.5. Is the difference between the mean scores for men and women significant at the 1% level? Give appropriate statistical evidence to justify your answer.

The manager of a major retail store has taken a random sample of 25 customers. The average sale was $52.50. The population standard deviation is known to be $6.10. The manager would like to determine whether or not the mean sales by all customers are significantly more than $50. What is the p-value for the test?

An IQ test has a mean of 96 and a standard deviation of 15. Which is more​ unusual, an IQ of 81 or an IQ of 120​?

An instructor claims that the average number of hours needed to study for a final exam in order to pass should be 5 hours. A student believes that the instructor is understating the number of hours needed to pass and surveys 36 students and finds the sample mean and standard deviation to be 5.7  and 1.5 hours respectively.  Test the instructors claim at a .10 level.