问题如下:
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:
选项:
A.1.96.
B.3.99.
C.5.36.
解释:
C is correct.
At the 95% level of significance, the critical value is .
So the confidence interval is ,
From the equation t 32.5 + 1.96 σ = 43 or 32.5 - 1.96σ = 22, we get
可以具体讲一下什么情况的standard error要除以根号n,什么时候不用吗?不是特别懂