Card 39 / 180: The average monthly cell phone bill of a random sample of 256 residents of a city is $90 with a sample standard deviation of $24. What will be the 90% confidence interval for the mean monthly phone bills of all residents?
A) $87.53 to $92.48
B) $87.06 to $92.94
C) $50.40 to $129.60
D) $42.96 to $137.04

Keyboard Shortcuts