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Unformatted text preview: degfreedom=n − 1 t∗ =TINV(0.05,5-1)=2.776. Q. If we were to know σ , the we would
had used the Normal Distrib. What is the
equivalent CI for 2.776? t(4) Applet:
StudentsTDistributionAndItsNormalApproxi 0.025 0.025
5 4 3 2 1 0 Rafael Mendoza
Elementary Business Statistics – Class 14 1 2 t* 3 4 5 McCombs The diﬀerence between population means? Why are we interested in the diﬀerence between population means?
Retail stores might be interested in how much more (or less), on
average, a woman spends on a typical purchase occasion than a man.
Which airline company has less average delay on Houston-Austin
Does mailing coupons increase or decrease the average amount spent
on a product?
Do husbands react to car sales presentations more positively than
their wives? Rafael Mendoza
Elementary Business Statistics – Class 14 McCombs Paired Sample Design
Samples we want to compare are
paired in some natural way
Pretest-posttest for each person,
husband-wife pairs Paired Sample Analyze the diﬀerences for each pair
using the standard CI arguments
Excel Example: Husband and wife
reactions to Sales Presentations
You can use Excel or StatTools to
compute the conﬁdence interval Excel Example: Stocks Rafael Mendoza
Elementary Business Statistics...
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- Fall '07