1 HW #4 1) A psychology professor of a large class became curious as to whether the students who turned in tests first scored differently from the overall mean on the test. The overall mean score on...

This homework is based on chapter 5. I have attached the textbook. Must show work. Thank you


1 HW #4 1) A psychology professor of a large class became curious as to whether the students who turned in tests first scored differently from the overall mean on the test. The overall mean score on the test was 75 with a standard deviation of 10; the scores were approximately normally distributed. The mean score for the first 20 students to turn in tests was 78. Using the .05 significance level, was the average test score earned by the first 20 students to turn in their tests significantly different from the overall mean? a. Use the five steps of hypothesis testing. ❶ Restate the question as a research hypothesis and a null hypothesis about the populations. Null Hypothesis: Research Hypothesis: ❷ Determine the characteristics of the comparison distribution. Distribution of means: ?? = ?? = Shape = _____ ❸ Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected. Cut off ( ________ level, ____ tailed) = ______ ❹ Determine your sample’s score on the comparison distribution. ❺ Decide whether to reject the null hypothesis. a. Sketch the distributions involved. 2 2) Dr. Drake Ramoray is interested in the effect of taking vitamins has on fitness in Central Perk workout center. The average score on a fitness test for was 58 with a standard deviation of 10 for all those who workout there. After starting the vitamins, Dr. Drake Ramoray tested 50 participants and found their mean to be 52. Using the .01 level of significance, was this difference significant? a. Use the five steps of hypothesis testing. ❶ Restate the question as a research hypothesis and a null hypothesis about the populations. Null Hypothesis: Research Hypothesis: ❷ Determine the characteristics of the comparison distribution. Distribution of means: ?? = ?? = Shape = _____ ❸ Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected. Cut off ( ________ level, ____ tailed) = ______ ❹ Determine your sample’s score on the comparison distribution. ❺ Decide whether to reject the null hypothesis. b. Sketch the distributions involved. 3 3) The head of public safety notices that the average driving speed at a particular intersection averages 35 mph with a standard deviation of 7.5 mph. After a school speed limit sign of 20 mph is placed at the intersection, the first 40 cars travel past at an average speed of 32 mph. Using the .01 significance level, was there a significant change in driving speed? c. Use the five steps of hypothesis testing. ❶ Restate the question as a research hypothesis and a null hypothesis about the populations. Null Hypothesis: Research Hypothesis: ❷ Determine the characteristics of the comparison distribution. Distribution of means: ?? = ?? = Shape = _____ ❸ Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected. Cut off ( ________ level, ____ tailed) = ______ ❹ Determine your sample’s score on the comparison distribution. ❺ Decide whether to reject the null hypothesis d. Sketch the distributions involved. 4 4) A school psychologist interested in the effect of a program designed to reduce adjustment problems in newly transferred students knew from her years of working at the school that the average score on a scale of adjustment difficulties for transfer students was 58 with a standard deviation of 10. After starting the program, the psychologist tested 50 students and found their mean to be 52. Using the .01 level of significance, was this difference significant? a. Use the five steps of hypothesis testing. ❶ Restate the question as a research hypothesis and a null hypothesis about the populations. Null Hypothesis: Research Hypothesis: ❷ Determine the characteristics of the comparison distribution. Distribution of means: ?? = ?? = Shape = _____ ❸ Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected. Cut off ( ________ level, ____ tailed) = ______ ❹ Determine your sample’s score on the comparison distribution. ❺ Decide whether to reject the null hypothesis b. Sketch the distributions involved.