ECON 2B03 Lecture Notes - Lecture 17: Sampling Distribution, Statistical Parameter, Alternative Hypothesis
19 Jan 2014
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The t-distribution and confidence intervals when 2 is unknown. So far we have examined the sampling distribution of the sample mean. If: the population is normally distributed, or, the sample size is large, say n 30. Usually the variance is unknown, and we must estimate it using s2. This substitution of s2 for 2causes aminor problem, has a normal distribution because the z-score no longer. Is called the t-score and it has a t-distribution with n-1 degrees of freedom. A (1-a) x 100% confidence interval for istherefore given by x t a. Note that the t-score follows a t-distribution when: the population is normal and the sample size is large or small, the population is non-normal and sample is large (i. e. , A hypothesis is a statement about the value or set of value or set of values that a parameter or group of parameters can assume (proposition tentatively as possibly true)
