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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
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
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
(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.
- Fall '07