STA 144 Week 6 Homework

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California Baptist University *

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Jan 9, 2024

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STA 144 HOMEWORK 6 STA 144 Homework 6 Zihao Luke. Gao College of behavior and social sciences, Cal Baptist University Dr. McKinney Dec 9th, 2023

STA 144 HOMEWORK 6 STA 144 Week 6 Homework Work on the following problem set from chapter 11 1. Using the data in the file named Chapter 11 Data Set 2 (in the appendix), test the research hypothesis at the .05 level of significance that boys raise their hand in class more often than girls. Do this practice problem by using SPSS or by hand. What is your conclusion regarding the research hypothesis? Remember to first decide whether this is a one or two-tailed test. This is a two tailed test and the p value is at .044 which is below the value of .05 which is the significance level so we fail to reject the hypothesis. 2. Using the same data set (Chapter 11 Data Set 2), test the research hypothesis at the .01 level of significance that there is a difference between boys and girls in the number of times they raise their hand in class. Do this practice problem by using SPSS or by hand. What is your conclusion regarding the research hypothesis? You used the same data for this problem as for Question 1, but you have a different hypothesis (one is directional and the other is nondirectional). How do the results differ and why?

STA 144 HOMEWORK 6 This is a two tailed test and since the p value is at .044 so we reject the null hypothesis at the significance level of .01. The difference from question one is that the significance level went from .05 to .01 which makes easier to reject the null hypothesis than question one. 3. Time for some tedious, by-hand practice just to see if you can get the numbers right. Using the following information, calculate the t-test statistics by hand. a. X1 = 62 X2 = 60 n1 = 10 n2 = 10 s1 = 2.45 s2 = 3.16 Degree of freedom is 18, pooled sd is 2.8275, t = 1.582 b. X1 = 158 X2 = 157.4 n1 = 22 n2 = 26 s1 = 2.06 s2 = 2.59 Degree of freedom is 46, Pooled so is 2.3628, t = 8.77 c. X1 = 200 X2 = 198 n1 = 17 n2 = 17 s1 = 2.45 s2 = 2.35 Degree of freedom is 32, pooled so is 2.40, t = 2.43 4. Using the results you got from Question 3, and a level of significance of .05, what are the two- tailed critical values associated with each? Would the null hypothesis be rejected? A. Two tailed value is 2.10, fail to reject the null B. Two tailed value is 2.01, fail to reject the null C. The two tailed value is 2.04, fail to reject the null 5. Here’s a good one to think about. A public health researcher tested the hypothesis that providing new car buyers with child safety seats will also act as an incentive for parents to take other measures to protect their children (such as driving more safely, child-proofing the home, etc.). Dr. L counted all the occurrences of safe behaviors in the cars and homes of the parents who accepted the seats versus those who did not. The findings? A significant difference at the .013 level. Another researcher did exactly the same study, and for our purposes, let’s assume that everything was the same — same type of sample, same outcome measures, same car seats, and so on. Dr. R’s results were marginally significant (remember that from Chapter 9?) at the .051 level. Whose results do you trust more and why?

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