1) In a recent sample, 42 out of 500 randomly selected G.E. light bulbs were defective.

a) Find the point estimate, ^p , and find z a/2 for a 95% confidence interval.

b) Find the margin of error, E, and describe 95% confidence interval for the proportion of all G.E.

light bulbs that are defective.

c) Interpret the confidence interval you found in part a.

d) You would like to have a narrower confidence interval (smaller error) with the same sample

Circle the correct choice to make that happen.

i) Raise your level of confidence to 98% or 99%

ii) Lower your level of confidence to 90%

2) I asked 1,200 randomly selected people if they believe that UFO's are real.319 of them said yes.

Construct a 90% confidence interval for the percentage of all people who believe UFO's are real.