The population is 6000 programmer which is supposed to be normally distributed. A sample with 100 size is drawn from the population. Based on z-statistic, 95% confidence interval of sample mean of annual salary is 32.5 (in thousands) dollars ranges from 22 (in thousands) dollars to 43 (in thousands) dollars .Calculate the standard error of mean annual salary:
这题如何看出22-43是表示置信区间呀？ 可以用计算器算出22-43的S为啥不能用？ 22-43算出的平均数就是题目给的32.5呀
