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## Upper-tailed t-test

Cheap N Fresh food stores advertise that their average checkout waiting time is 4 minutes or less. A random selection of shoppers at peak time yielded the following waiting times: 3.5, 5.0, 3.8, 4.5, 7.2, 5.0. Does this evidence disprove the store's claim?

1.
Hypotheses: versus
2.
Test Statistic:
3.
P-value: Presuming H0 is true, the likelihood of chance variation yielding a t-statistic higher than 1.55 (this is the H1 direction) is .09.

4.
Conclusion: Since P-value > .05, we do not reject H0. The sample does not provide enough evidence to disprove the store's claim.

Summary of the upper-tailed  t-test for :

versus
Test statistic:
P-value: Total area greater than t (the direction of H1) under t-curve with n-1 degrees of freedom. If t is far enough above 0 (the direction of H1), the P-value will be small.
Conclusion: If P-value .05, we reject H0 with statistical significance. If P-value .01, we reject H0 with high statistical significance. If P-value>.05, we do not reject H0.

Next: Two-tailed t-test Up: Test of Significance involving Previous: Test of Significance involving

2003-09-08