PSY230 Intro Statistics-Section X CH 8-9 Problems - Google Docs X Problems Ch 8-9 + C CH 8-9 Problems.pdf 230 25242 learn.maricopa.edu/courses/1278085/assignments/13299574?module_item_id=27320573 Assignments > Problems Ch 8-9 Page < 6 of 20 Ch. 8- Computing Independent-Samples t Tests: For the examples below, go through the steps of hypothesis testing using the Independent-Samplest Test, and answer the questions in each table. (see text pp. 259-282, online calculators, & Stat Sheet Ch.8) EXAMPLE A: The following data are from a study comparing Chemistry Examination Scores between an Experimental Group and Control Group of subjects. The Experimental Group received a chemistry lesson in a motion- picture presentation, while the Control Group received the same lesson in a slide-show presentation. The data consists of the correct scores on a follow-up examination. There are 10 subjects total, 5 in each group. Helpful Hint: Use the online analysis bok to perform calculations EXAMPLE A: Ceny QUESTIONS: Car Cano a. What groups are being compared? 1. Control (slideshow), 2. Experimental (motion picture) b. What is the dependent variable in the study? c. List the Hypotheses: Chemistry Exam Score Null-Exam scores will be the same for the two instruction methods. Alternative-Exam scores will differ for the two instruction methods. d. State the decision rule & mark the critical values of t for the hypothesis test. f. For alpha-.05, 2-tailed test Equation 8.1: df=N-2, df=10-2=8 Critical values = +/- 2.306 Calculate the test statistic for the sample data: M-M, Sample 1: Sample 2: M-314 M-30 N-5 Compute the Cohen's d Effect Size & interpret. M M +2306 *** Use online calculator to compute*** t=.53 *** Use online calculator for Ch. 8 Cohen's d*** d=333, Fairly small effect g. Interpret the Results. What Decision should be made based on the statistical test? The calculated test statistic was in the COMMON ZONE, so was NOT significant. Accept the Null Hypothesis. h. Write a specific conclusion about the test results. Found no evidence to support a difference in chemistry exam scores between the two instruction method groups. CH 8-9 Problems M Page 5 of 19 Download Info Close ZOOM + Feb 6 11:07 PSY230 Intro Statistics-Section X CH 8-9 Problems - Google Docs X Problems Ch 8-9 + C learn.maricopa.edu/courses/1278085/assignments/13299574?module_item_id=27320573 CH 8-9 Problems.pdf 230 25242 Assignments > Problems Ch 8-9 Page 8 of 20 STUDY 1: Dougall compared the resting heart rate of average healthy citizens with that of soldiers suffering from post-traumatic stress disorder (PTSD). The normal resting heart rate for sample of 25 healthy people averaged 65 beats per minute (bpm) with a standard deviation of 6 bpm. The average heart rate of sample of 16 people suffering from PTSD was 82 bpm with a standard deviation of 8 bpm. Are soldiers suffering from PTSD different in resting heart rate from normal citizens? Use the standard decision rule of alpha level, a = .05 for a two-tailed hypothesis test. QUESTIONS: a. What groups are being compared in the study? b. What is the dependent variable in the study? c. List the Hypotheses: Null- Alternative- d. State the decision rule & locate/mark on the distribution below, the critical values of t for the hypothesis test. e. Calculate the test statistic for the sample data: f. Compute the Cohen's d Effect Size & interpret. CH 8-9 Problems M Page 7 of 19 Download Info Close ZOOM + Feb 6 11:07 PSY230 Intro Statistics-Section X CH 8-9 Problems - Google Docs X Problems Ch 8-9 + learn.maricopa.edu/courses/1278085/assignments/13299574?module_item_id=27320573 CH 8-9 Problems.pdf 230 25242 Assignments > Problems Ch 8-9 Interpret the Results. What decision should be made based on the statistical test? Page < 9 of 20 ( h. Write a SPECIFIC short narrative conclusion about the hypothesis test results. M Download Info Close Screen capture now Screenshot taken Show in folder ZOOM + Copied to clipboard Search + V Edit Delete Feb 6 11:07 PSY230 Intro Statistics-Section X CH 8-9 Problems - Google Docs X Problems Ch 8-9 + C learn.maricopa.edu/courses/1278085/assignments/13299574?module_item_id=27320573 CH 8-9 Problems.pdf 230 25242 > Assignments > Problems Ch 8-9 STUDY 2: Page < 10 of 20 A researcher examines the short-term effect of a single treatment with acupuncture on cigarette smoking. 16 subjects who smoke approximately a pack of cigarettes a day are assigned to one of two groups. One group receives the treatment with the acupuncture needles. The second group of subjects serves as a control group and is given relaxation instruction while on the examining table but no acupuncture treatment. The number of cigarettes smoked the next day is recorded for all subjects. For the following data, determine if there is a significant difference in cigarette consumption between the Control & Acupuncture groups. Use the standard decision rule of alpha level, a = 05 for a two-tailed hypothesis test. Control Group #Cigarettes Smoked Acupuncture Group #Cigarettes Smoked Subject 1 21 Subject 1 18 Subject 2 22 Subject 2 10 Subject 3 17 Subject 3 12 Subject 4 18 Subject 4 22 Subject 5 30 Subject S 20 Subject 6 24 Subject 6 18 Subject 7 20 Subject 7 10 Subject 8 11 Subject 8 7 QUESTIONS: a. What groups are being compared in the study? b. What is the dependent variable in the study? c. List the Hypotheses: Null- Alternative- CH 8-9 Problems A Page 9 of 19 Download Info Close ZOOM + Feb 6 11:07 PSY230 Intro Statistics-Section X CH 8-9 Problems - Google Docs X Problems Ch 8-9 + learn.maricopa.edu/courses/1278085/assignments/13299574?module_item_id=27320573 CH 8-9 Problems.pdf 230 25242 Assignments > Problems Ch 8-9 d. State the decision rule & locate/mark on the distribution below, the critical values of t for the hypothesis test. e. What is the average cigarettes smoked for the Control Group? f. What is the average cigarettes smoked for the Acupuncture Group? 8 Calculate the test statistic for the sample data: i. Compute the Cohen's d Effect Size & interpret. Interpret the Results. What decision should be made based on the statistical test? j. Write a SPECIFIC short narrative conclusion about the hypothesis test results. CH 8-9 Problems M Page 11 of 20 Download Info Close Screen capture now Screenshot taken Show in folder ZOOM + Copied to clipboard Search + V Page 10 of 19 Edit Delete Feb 6 11:07