A random sample of high temperatures for 12 recent New Year days had a mean of 42°F. Assume the variable is normally distributed, and the standard deviation of the sample temperatures was 8°F. Find the 95% confidence interval of the population mean for the temperatures.
a) (37°F, 47°F)
b) (38°F, 46°F)
c) (39°F, 45°F)
d) (40°F, 44°F)
