单选题
编号：2690445
1. A random sample of 100 computer store customers spent an average of $75 at the store. Assuming the distribution is normal and the population standard deviation is $20, the 95% confidence interval for the population mean is closest to:
- A.$71.08 to $78.92.
- B.$73.89 to $80.11.
- C.$74.56 to $79.44.