the owner of ** wanted to know the averaga age of its clients, a random sample of 25 tourists is taken.it shows a mean age of 46 years with a standard deviation of 5 years.
The margin of error of a 98 percent CI for the true mean client age is approximately.

T统计量和Z有什么不同，分别用在什么情况下 啊？
算出的答案不同吗
不好意思统计很差- - 望指点呀= =