Question

please show how its done on TI-64

1. SAT scores are distributed with a mean of 1,500 and a standard deviation of 300. You are interested in estimating the average SAT score of first year students at your college. If you would like to limit the margin of error of your 95% confidence interval to 25 points, how many students should you sample?

3. If n=31, ¯xx¯(x-bar)=36, and s=6, construct a confidence interval at a 98% confidence level. Assume the data came from a normally distributed population.

(--------)< μμ < (--------)

5. You measure 42 textbooks' weights, and find they have a mean weight of 43 ounces. Assume the population standard deviation is 14.2 ounces. Based on this, construct a 90% confidence interval for the true population mean textbook weight.

(--------)< μμ < (--------)

7. A student was asked to find a 98% confidence interval for widget width using data from a random sample of size n = 25. Which of the following is a correct interpretation of the interval 13.6 < μ < 25.9?

Check all that are correct.

a. There is a 98% chance that the mean of the population is between 13.6 and 25.9.

b. There is a 98% chance that the mean of a sample of 25 widgets will be between 13.6 and 25.9.

c. With 98% confidence, the mean width of a randomly selected widget will be between 13.6 and 25.9.

d. The mean width of all widgets is between 13.6 and 25.9, 98% of the time. We know this is true because the mean of our sample is between 13.6 and 25.9.

e. With 98% confidence, the mean width of all widgets is between 13.6 and 25.9.

Answer 1