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# A random sample of 85 students has a mean score of 265 with

### Customer Question

A random sample of 85 students has a mean score of 265 with a standard deviation of 55 on a test. This test results in the state declaring the mean score is more than 260. At a=0.05, is there enough evidence to support the administators claim?
Submitted: 7 years ago.
Category: Homework
Expert:  SteveS replied 7 years ago.

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Customer: replied 7 years ago.
z(alpha) is 0.05, isn't the z score 1.96? i.e. 90%
Expert:  SteveS replied 7 years ago.
z(alpha) = 1.96 for a two-tailed test, z(alpha) = 1.645 for a one-tailed test. In this problem, it's a one-tailed test, so we use 1.645 as the z score. Either way, the conclusion remains the same.
Customer: replied 7 years ago.