RSCH 665 A5.3 Name: Date: Q1. Background Method - (justify type of t-Test used) - (justify type of test) [directional/non-directional] - (identify alpha level used to test the null hypothesis) Results - Report descriptive statistics (discuss high points of statistical outcomes) - Assess normality assumption (discuss distributional symmetry) - Assess equal variance assumption (report and interpret results of Levene's test) (state null hypothesis) (interpret results using the p-value) (decision) [reject/retain null hypothesis] Conclusion (explain whether the drug decreased reaction time) Q2. Background Method - justify type of t-Test used - justify type of test (directional/non-directional) - identify alpha level used to test the null hypothesis Results - Report descriptive statistics - Assess normality assumption - Assess equal variance assumption decision: (reject/retain null hypothesis] Conclusion (explain whether the number of flight hours differed between low and high GPA students) t-test Problems Question 1. A researcher wishes to learn if a certain drug affects the reaction time of pilots to air traffic control instructions. She obtained a sample of pilots and randomly divided them into two groups. She then had one pilot group take the drug and used the second group as a control. Pilots were given headsets and given commands from an air traffic controller. The reactions times for each group of pilots is below. The researcher is interested in learning if the drug reduces the reaction time. Her hypothesis is: The mean reaction time in group A will be less than the mean in group B. Group A Group B Treated with Drug Control- Not Treated 0.72 0.71 0.68 0.83 0.69 0.89 0.66 0.57 0.57 0.68 0.66 0.74 0.70 0.75 0.63 0.67 0.71 0.80 0.73 0.78 A t-test can be used to test the probability that the two means do not differ. The alternative is that the reaction times from the group treated with the drug will not be less than that from the control group. This is a one-tailed test because the researcher is interested in if the drug decreased reaction time. She is not interested in if the drug changed reaction time. Question 2. A researcher wishes to learn whether the GPA of incoming flight students may be a factor in the number of flight hours the student completes in the first semester of college. The researcher has collected the flight hours of a random sample of students in a group of high GPA students and low GPA students. Low GPA High GPA 42 43 45 51 40 56 37 40 41 32 41 54 48 51 50 55 45 50 46 48 The researcher is testing whether GPA may be a factor in differences in flight time accumulated in the first semester at college. Their hypothesis is: The mean flight time of students with a low GPA is different than those incoming students with a high GPA. A t-test can be used to test the probability that the two means do not differ. The alternative is that the means differ; one of them is greater than the other. This is a two-tailed test because the researcher is interested in if GPA changes flight time