Introduction to Hypothesis Testing266CHAPTER 8and plans to administers the test to a sample of25 of today's high school students. Tenago, the scores on this IQ test produced a standard-ized distribution with a mean of pstandard deviation o =treatment effect and plans to use a two-tailed hypoth-esis test with ayearsn == .05.100 and aa. Compute the power of the test if the researcher uses9 individuals. (See Example 8.6.)of the test if the researcher15. If there actually has beena sample of na 7-point increase in the average IQ during the10 years, then find the power of the hypothesis testb. Computepastthepower16 individuals.uses a sample of n20. A researcher plans to conduct an experiment evalu-ating the effect of a treatment. A sample of n = 9participants is selected and each person receives thetreatment before being tested on a standardized dex-terity task. The treatment is expected to lower scoreson the test by an average of 30 points. For the regularpopulation, scores on the dexterity task form a normaldistribution with ufor each of the following.a. The researcher uses a two-tailed hypothesis test.05 to determine if the data indicate a10with a =significant change in IQ over the pastb. The researcher uses a one-tailed hypothesis testwith ayears..05 to determine if the data indicate apast 10 years.significant increase in IQ over the240 and o =30.22. Briefly explain how increasing sample size influenceseach of the following. Assume that all other factorsa. If the researcher uses a two-tailed test witha= .05, what is the power of the hypothesis test?are held constant.b. Again assuming a two-tailed test witha =.05,a. The size of the z-score in a hypothesis test.b. The size of Cohen's d.what is theof the hypothesis test if thepowersample size is increased to n25?of a hypothesis test.Theс.power21. Research has shown that IQ scores have been increas-ing foris called the Flynn effect and the data indicate that theincreaseyears (Flynn, 1984, 1999). The phenomenon23. Explain how the power of a hypothesis test is influ-enced by each of the following. Assume that all otherfactors are held constant.about 7 points pertodecade.appearsaverageTo examine this effect, a researcher obtains an IQ testa. Increasing the alpha level from .01 to .05.b. Changing from a one-tailed test to a two-tailed test.with instructions for scoring from 10years ago