Discuss te below;
GE fluorescent bulbs have a useful lifetime which is normally distributed. We wish to estimate mean lifetime. A random sample of 20 bulbs yields the following results: sample mean= 2,360 hours and a sample standard deviation of 365 hours.
a. Analyze the output above to determine the 95% confidence interval for the mean lifetime of GE fluorescent bulbs. Interpret this confidence interval.
b. Suppose a GE executive says. "Our florescent bulbs have an average expected lifetime of 2500 hours." Could the executive be correct? Explain.
Table
Confidence interval-mean
95% confidence level
2360 mean
365 Std dev
20 N
2093 t(df-19)
170.825 half width
2630.825 Upper confidence limit
2189.175 Lower confidence limit