1. 459 randomly selected light bulbs were tested in a laboratory, 291 lasted more than 500 hours. Find a point estimate of the true proportion of all light bulbs that last more than 500 hours.
2. Find the critical value for zα/2 that corresponds to a degree of confidence of 98%.
3. Find the margin of error for the 95% confidence interval used to estimate the population proportion with n = 163 and x = 96.
4. Construct the confidence interval for question 3.
5. Interpret the confidence interval found in question 4.
6. What are the requirements for a Student's t-distribution?
7. Find the critical value for tα/2 corresponding to n = 12 and 95% confidence level.
8.Use the confidence level and sample data to find the margin of error E.
College students' annual earnings:
99% confidence, n = 81, x- = $3967, s = $874
9. Construct the confidence interval for question 8 above.
10. Interpret the confidence interval found in question 9.