SOLUTION: From a population which can only be approximated by a normal distribution, a sample of [n=25 elements] is selected and the standard deviation of the sample is computed. For the int

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Question 867794: From a population which can only be approximated by a normal distribution, a sample of [n=25 elements] is selected and the standard deviation of the sample is computed. For the interval estimation of the population mean, the proper distribution to use is the:
a. Normal distribution
b. T distribution
c. T distribution with 25 degrees of freedom
d. T distribution with 24 degrees of freedom
e. None of the above
Answer by jim_thompson5910(35256) About Me  (Show Source):
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Some books vary (since it's not a hard fast rule), but in most cases I've seen that you use the t distribution if you don't know the population standard deviation and n <= 30.


Since n <= 30 is true and we don't know population standard deviation, we use the t distribution.


The degrees of freedom would be n-1 = 25-1 = 24.


So the answer is d. T distribution with 24 degrees of freedom