Attempts Average S 4 GravetterWallnau Essentials Chapter 9En

Attempts: Average: /S 4. Gravetter/Wallnau Essentials Chapter 9-End-of-chapter question 8 Aa Aa A random sample of n = 25 individuals is selected from a population with -20, and a treatment is administered to each individual in the sample. After treatment, the sample mean is found to be M 22.2 with SS-384. Use the Distributions tool below to help answer the questions that follow. Degrees of Freedom = 21 -3.0 2.0 0.0 1.0 2.0 3.0 How much difference is there between the mean for the treated sample and the mean for the original population? (Note: In a hypothesis test, this value forms the numerator of the t statistic.) If there is no treatment effect, how much difference is expected between the sample mean and its population mean? That is, find the standard error for M. (Note: In a hypothesis test, this value is the denominator of the t statistic.)

Solution

Difference in mean = 22.2-20 = 2.2

Standard error = sqrt(384/25) =

=3.919

critical t statistic = t(0.025,24)

=0.5099

Sample t value

=2.2/3.919

=0.5613

Conclusion:

A