Lecture_14 (short)

# Assumption population distribution is normal the

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Unformatted text preview: distribution with n − 1 degrees of freedom, and we use TINV function. Assumption: Population distribution is Normal. The conﬁdence intervals produced using t-distributions are robust to violations of normality in the population especially if the sample size is large. Rafael Mendoza Elementary Business Statistics – Class 14 McCombs Properties of the t distributions The density curve of the t-distribution is symmetric and bell-shaped. Normal vs. t-distribution The curve is more spread out than the standard normal curve (due to substituting s for σ ). k = n − 1 is called the degrees of freedom. There is a diﬀerent t(k) distribution for each integer, k. Rafael Mendoza Elementary Business Statistics – Class 14 McCombs Properties of the t distributions - continued Q.2 As the degrees of freedom (k) increase, the t distribution moves . . . . . . the Standard Normal distribution. (a) farther away from (b) closer to Rafael Mendoza Elementary Business Statistics – Class 14 N...
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## This document was uploaded on 02/19/2014 for the course STA 309 at University of Texas at Austin.

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