Extraterrestrials

Here is an example of a two tailed hypothesis test.

For a two-tailed test you have to find the z-value and then take the p-value to be twice the area of the tail you get. Since for a two-tailed test the alternative hypothesis is we have to allow that the test statistic could be bigger than or it could be smaller than . That is why we need two tails.

Hmm… even if USA Today is right I’m beginning to wonder under what conditions people did see an extraterrestrial. Late at night I bet…

Problem adapted from Larson/Farber’s Elementary Statistics