1. An educational psychologist wants to test whether a new teaching method negatively affects reading comprehension scores using a significance level of 0.10. The mean reading comprehension scores of students taught using the old method has a value of 73.1 and are normally distributed. A sample of 31 students taught with the new method has a mean reading comprehension score of 67.8 and a standard deviation of 14.0. My sample t-statistic equals -2.11 and is more extreme than the critical value t = -1.31. The Null Hypotheses: a. if it were true, i probably would not have gotten this result. b. probably false. c. If false, probably would have gotten this result. d. Is definitely false.
2. A clinical psychologist wants to investigate whether patients who have suffered childhood abuse have a higher level of self-efficacy as adults compared to the general population of US adults. Assume scores on the self-efficacy questionnaire (SEQ) for the general population of US adults are distributed normally with a mean of 117.8. A sample of 29 US adults who suffered childhood abuse has a mean score on the SEQ of 119.1 and a standard deviation of 6.0. The significance level for the test is equal to 0.10. What is/are the critical value(s) of the test statistic? a. +1.31. b.+/-1.70. c.-1.31. d.+1.70.
3. A pharmaceutical company wants to test whether taking their new anti-anxiety drug has the side effect of affecting systolic blood pressure of patients using a significance level of 0.05. Assume SBPs in the population of US adults are distributed normally with a mean of 126.2. A sample of 29 US adults patients treated with the new drug has a mean SBP of 122.9 and a standard deviation of 21.0. What is the value of the test statistic? Enter value with three decimals.