Question

classify the hypothesis test as two - tailed, left - tailed, or right - tailed.
at one school, the average amount of time that tenth - graders spend watching television each week is 20.5 hours. the principal introduces a campaign to encourage the students to watch less television. one year later, the principal wants to perform a hypothesis test to determine whether the average amount of time spent watching television per week has decreased from the previous mean of 20.5 hours.
left - tailed
right - tailed
two - tailed

Explanation:

Step1: State the null and alternative hypotheses

Let \(\mu\) be the population mean of the amount of time spent watching television per week. The null hypothesis \(H_0:\mu = 20.5\) (no change from the previous mean). The alternative hypothesis \(H_1:\mu<20.5\) (the mean has decreased).

Step2: Determine the type of test

In a hypothesis test, if the alternative hypothesis has the form \(H_1:\mu <\mu_0\) (where \(\mu_0 = 20.5\) in this case), the test is left - tailed. The critical region is in the left - hand tail of the sampling distribution.

Answer:

Left - tailed