Kizspy | Question: 29
(Choose 1 answer)
(See picture)
Α. (394; 406)
Β. (392; 408)
C. (393; 407)
D. (395; 405)
E. None of the other choices is correct
A random sample of 79 light bulbs had a mean life of 400 hours. Construct a 90%confidence interval for the mean life of all light bulbs of this type. Assume that the standard deviation of all light bulb's life is known to be 28 hours.Let 20.05 = 1.645; 20.1 = 1.282.
