Question

A company manufactures light bulbs. The company wants the bulbs to have a mean life span of 991 hours. This average is maintained by periodically testing random samples of 16 light bulbs. If the​ t-value falls between -t0.95 and t0.95​, then the company will be satisfied that it is manufacturing acceptable light bulbs. For a random​ sample, the mean life span of the sample is 999 hours and the standard deviation is 22 hours. Assume that life spans are approximately normally distributed. Is the company making acceptable light​ bulbs? Explain.

The company "is/is not making acceptable" light bulbs because the​ t-value for the sample is t= _____ and t0.95= _______ (Round to two decimal places as needed.)

Answer 1

Sol m Given data The number of light bulbs (m)' = 16 The Sample Sample mean (x) = 999 hours The Standard dendalion (s) = 22 hours = n-1 degree of freedom de = 16-1 de = = 15 X-M to 3156 mean (4) : 991 hours 999 - 991 22/176 8 11 22/4 8 5.5 t 1,45