1. If the mean for scores on an exam is 72, and the standard deviation is 10, what is the z-score for a 79?
2. I take a sample of 26 people who tell me their scores on an IQ test. My sample has a mean of 108 and a standard deviation of 12. Starting with the lower limit, I am 95% confident that the true population mean lies between and .
3. A critic of Brooklyn College states that the mean high school GPA of newly admitted freshmen is 80. You run a hypothesis test to show that the true population mean is different from 80. The mean is 81.09, the standard deviation is 6.01; and your sample size is 10. What is the value of t? (Remember to round to hundredths).
4. A critic of Brooklyn College states that the mean high school GPA of newly admitted freshmen is 80. You run a hypothesis test to show that the true population mean is different from 80. Using the t-test table, and an alpha-level of 0.05, and the sample given in question 13, what is critical t?