In order to determine the average amount spent in November on Amazon.com a random sample of 153 Amazon accounts were selected. The sample mean amount spent in November was $253.78 with a standard deviation of $23.45. Assuming conditions are met, what is a 90% confidence interval for the population mean amount spent on Amazon.com in November?
a.) ($250.64, $256.92)
b.) ($251.34, $256.22)
c.) ($250.66, $256.90)
d.) ($247.47, $260.09)