Statistics PRACTICE PROBLEMS (1) Suppose we know that the average of systolic blood pressure for American college female students is 110 mmHg. We randomly selected 100 college female students from a college and obtained their systolic blood pressure. The average SBP of these women was 115 mmHg and standard deviation was 20mmHg. To examine if there is difference for the average SBP of this college female students with American college female students, what is the null hypothesis? a. μ = 110 b. μ = 115 c. μ = μ2 d. μ1 ≠ μ2 (2) If in the above question, we got a z-score = 2.5. What statistical decision can we reach? a. Reject Ha and conclude that the female students of this college has the same SBP as the national level b. Reject Ha and conclude that the female students of this college has a higher SBP than the national level c. Reject H0 and conclude that the female students of this college has the same SBP as the national level d. Reject H0 and conclude that the female students of this college has a higher SBP than the national level (3) In the above question, what would occur if we conclude that the female students of this college has the same SBP as the national level, when in fact the female students of this college has a higher SBP than the national level? a. Type I error b. Type II error c. Power d. Lack of precision (4) Suppose we are going to test the null hypothesis with the significance level α = 0.05. What z value will enable us to reject the null hypothesis? a. -1.96 ≤ z ≤ 1.96 b. z ≤ -1.96 or z ≥ 1.96 c. -1.645 ≤ z ≤ 1.645 d. z ≤ -1.645 or z ≥ 1.645 (5) Suppose we know that the average height of American women is 5' 4". If we drew a random sample of 200 women from Milwaukee and got their average height 5' 6". We want to conduct a hypothesis testing. What is appropriate null hypothesis? a. μ = 5' 4" b. μ = 5' 6" c. μ ≠ 5' 4" d. μ ≠ 5' 6" (6) For the above question, if we get a Z value = 1.21. What is our conclusion? a. Reject H0 and conclude that Milwaukee women are higher than average American women b. Reject H0 and conclude that the average height of Milwaukee women is 5' 4" c. Fail to reject H0 and conclude that Milwaukee women are higher than average American women. d. Fail to reject H0 and conclude that the average height of Milwaukee women is 5' 4" (7) In a clinical trial we want to test a new drug and a currently widely used drug in treating bacterial infections. What is the null hypothesis? a. The new drug cures more bacterial infections than the old drug does b. The new drug cures less bacterial infections than the old drug does c. There is no difference between the two drugs on average proportion of curing bacterial infections d. There is difference between the two drugs on average proportion of curing bacterial infections (8) If in the above question, we got a Z = -9.58. What statistical decision can we reach? a. Reject Ha and conclude that there is no difference between the two drugs on average proportion of curing bacterial infections b. Reject Ha and conclude that there is difference between the two drugs on average proportion of curing bacterial infections c. Reject H0 and conclude that there is difference between the two drugs on average proportion of curing bacterial infections d. Reject H0 and conclude that there is no difference between the two drugs on average proportion of curing bacterial infections (9) What would occur if we concluded that the there is no difference between the two drugs in treating bacterial infections, when in fact they are different in effect. a. Type I error b. Type II error c. Power d. Lack of precision (10) A study is conducted to examine IQ test scores for fourth grade students in Madison public schools. The test being used has a mean score 100 and standard deviation 15 in the general population. The investigators selected a sample of 20 fourth grade students attending Madison public schools. They want to test the null hypothesis of a mean score = 100 in this population. What test should they use? a. One-sample z test b. One sample t test c. Two-sample t test (i.e. independent t test) d. Paired t test (11) A study is conducted to examine IQ test scores for fourth grade students in Madison public schools. The test being used has a mean score 100 in the general population. The investigators selected a sample of 20 fourth grade students attending Madison public schools. They want to test the null hypothesis of a mean score = 100 in this population. What test should they use? a. One-sample z test b. One sample t test c. Two-sample t test (i.e. independent t test) d. Paired t test (12) A study is conducted to examine IQ test scores for fourth grade students to see if birth order is associated with test score. The test being used has a mean score 100 and standard deviation 15 in the general population. The investigators conducted IQ test to a sample of 25 siblings (first vs second born) when they were fourth grade students. They want to test the null hypothesis that the first born and second born have equal IQ scores. What test should they use? a. One-sample z test b. One sample t test c. Two-sample t test (i.e. independent t test) d. Paired t test (13) An intervention program was designed to improve reading abilities among fourth grade students. In order to evaluate whether the program is effective, researchers randomly assigned 100 children to intervention and control groups, and compared their reading test scores after 3 months. What test should they use? a. One-sample z test b. One sample t test c. Two-sample t test (i.e. independent t test) d. Paired t test (14) What you can tell from the following table? Source: Pinar Gul, et al. The efficacy of pre-operative instruction in reducing anxiety following gyneoncological surgery: a case control study. World Journal of Surgical Oncology 2011, 9:38 (14) Our dependent variable is categorical (“yes” cancer present, “no” cancer present) and we want to determine statistical differences for gender (male and female). What test should we use? a. Chi-square b. One sample t test c. Two-sample t test (i.e. independent t test) d. Paired t test
Purchase answer to see full attachment