Analyzing Fuse Production Process The Telektronic Company produces 20-amp fuses used to protect car radios from too much electrical power. Each day 400 fuses are randomly selected and tested; the results (numbers of defects per 400 fuses tested)

for 20 consecutive days are as follows:

10 8 7 6 6 9 12 5 4 7 9 6 11 4 6 5 10 5 9 11

a. Use a control chart for p to verify that the process is within statistical control, so the data can be treated as coming from a population with fixed variation and mean.

b. Using all of the data combined, construct a 95% confidence interval for the proportion of defects.

c. Using a 0.05 significance level, test the claim that the rate of defects is more than 1%.