Which of the following distributions is used when estimating the population mean from a normal population with unknown variance?
A)	the t-distribution with n+1 degrees of freedom
B)	the t-distribution with n degrees of freedom
C)	the t-distribution with n-1 degrees of freedom
D)	the t-distribution with 2n degrees of freedom
Answer:C
Which of the following distributions is used when estimating the population mean from a normal population with unknown variance?
A)	the t-distribution with n+1 degrees of freedom B)	the t-distribution with n degrees of freedom C)	the t-distribution with n-1 degrees of freedom D)	the t-distribution with 2n degrees of freedom