Hypothesis Test - Mean

Hypothesis Test - Mean

Author: mary daunis

- to illustrate a hypothesis testing procedure for a mean
- to show how the Student t distribution is used in a hypothesis test
- to show how to use hand calculations in a hypothesis testing procedure

Hypothesis testing is a very strange statistical process - we take a lot of time getting accustomed to what it is and to the logic behind it. This example should take away some of the mystery!
Just remember that a hypothesis test is just another way to think of a confidence interval - if you get confidence intervals, then hypothesis tests are not that difficult. So, go back to the section on confidence intervals and review that if you are having a lot of difficulty with the idea of hypothesis testing.

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Mean - Part 1

Part 1 gives the set-up to the problem. We will figure out what the Claim, Null and Alternative hypotheses are. Then, we will settle on the correct distribution and see where the critical region is.

Mean - Part 2

In the second part we calculate the test statistic and determine the critical value.

Mean - Part 3

We finish off this example by giving "regular language" wording to the final conclusion - it is important to do this so that an average person looking at your results will know what you mean by your conclusion.

Another Look at the Light Bulb Claim - Manufacturer's Perspective

The manufacturer is concerned with establishing the validity of the claim that the light bulbs last at least as long as 250 hours - so the claim is stated as such.

Another Look at the Light Bulb Claim - Consumer's Perspective

The consumer is concerned with faulty light bulbs - those that do not meet the manufacturer's stated burnout time - and so will state the claim to reflect that concern - bulbs last for a shorter time than the manufacturer says they do.