Total points are 40. Points are included with each problem.

Included with each section or problem are reference examples and end of section exercises that can be used as a guide. Be sure to show your work in case partial credit is awarded. To receive full credit, work must be shown if applicable.

Section 6.1: Confidence Intervals for the Mean (Large Samples)

1. Find the critical value zc necessary to form a confidence interval at the given level of confidence. (References: definition for level of confidence page 311, end of section exercises 5 - 8 page 317) (2.5 points each)

a. 90%

()

b. 80%

()

1. The new Twinkle bulb has a standard deviation hours. A random sample of 50 light bulbs is selected from inventory. The sample mean was...