From a population that is normally distributed, a sampleof 25 elements is selected and the standard deviation of the sampleis computed. For the interval estimation of , the properdistribution to use is the t distribution with 24 degrees offreedom......... correct? From a population that is normally distributed, a sampleof 25 elements is selected and the standard deviation of the sampleis computed. For the interval estimation of , the properdistribution to use is the t distribution with 24 degrees offreedom......... correct?
Explanation / Answer
Yes, this is correct. Different textbooks have differentrecommendation for when to use the t-distribution rather than thez-distribution, but all agree that the t-distribution should beused then n < 30, as it is here. When using the t-distribution, the formula for df is always n-1, soin this case that yields: 25-1 = 24