Question

The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The standard deviation is 98 hours. A random sample of 49 light bulbs indicated a sample mean life of 300 hours.

(a) Construct a 99​% confidence interval estimate for the population mean life of light bulbs in this shipment.

The 99% confidence interval estimate is from a lower limit of 263.9 hours to an upper limit of 336.1 hours.

(b) Do you think that the manufacturer has the right to state that the lightbulbs have a mean life of 350 hours? Explain.

Based on the sample​ data, the manufacturer (has / does not have)- (which one) the right to state that the lightbulbs have a mean life of 350 hours. A mean of 350 hours is (less than 2 / more than 3)- (which one) standard errors (below / above)- (which one) the sample​ mean, so it is (highly unlikely / likely)- (which one) that the lightbulbs have a mean life of 350 hours.

Answer of (b) ?

Answer 1