Letitia measured and recorded the brightness (in lumens) of three light bulbs for 5 hours. What was the combined brightness of the three light bulbs at the 2-hour mark?
A.
520 lumens
B.
1,484 lumens
C.
1,002 lumens
D.
974 lumens

Arandom sample of 45 observations results in a sample mean of 68. the population standard deviation is known to be 23 a. compute the margin of error at a 959% confidence interval. b. compute the 95% confidence interval for the population mean c. compute the 90% confidence interval for the population mean. d. compute the 75% confidence interval for the population mean