Stats Test 3 Missed Pretest Questions Flashcards
A research clinic is interested in understanding the impact of a new anti-anxiety medication. They conduct a study to determine if there is a difference in the proportion of participants with decreased anxiety levels who take the new medication and those who take a placebo. A random sample of study participants were assigned to the new anti-anxiety medication (38 participants) and placebo (39 participants) for a three month trial period. What statistical procedure should be used to answer this research question?
A. A two-sample z test for proportions
B. A one sample t test for means
C. A one sample t confidence interval for means
D. A one sample z-test for proportions
E. A one sample z confidence interval for proportions
F. A Matched pairs t test for means
G. A Matched pairs t confidence interval for means
H. A two sample t test for means
I. A two sample t confidence interval for means
J. A two-sample z confidence interval for proportions
A two-sample z test for proportions
A university counseling center is interested in how the anxiety level of students changes over the course of their college careers. A random sample of 534 first-year students and a random sample of 342 final-year students were given the anxiety assessments. Average anxiety levels (0-100) were extracted from the surveys. Estimate the true difference between the mean anxiety levels of all first-year students and all students in their final year at this university. What statistical procedure should be used to answer this research question?
A. A two sample t confidence interval for means
B. A one sample t test for means
C. A one sample t confidence interval for means
D. A one sample z-test for proportions
E. A Matched pairs t test for means
F. A Matched pairs t confidence interval for means
G. A two sample t test for means
H. A two-sample z test for proportions
I. A two-sample z confidence interval for proportions
J. Analysis of Variance (ANOVA)
A two sample t confidence interval for means
A university counseling center is interested in the effectiveness of a support group for students suffering from the effects of anxiety. Anxiety assessments (scored 0 to 100) of a random sample 104 students participating in the program were measured at the beginning and end of the support group period to calculate mean differences for each student. The mean of these differences was found to be -12.1, and the standard deviation was 15.2. Estimate the true mean difference anxiety score for all students participating in the anxiety support group. What statistical procedure should be used to answer this research question?
A. A Matched pairs t confidence interval for means
B. A one sample t confidence interval for means
C. A one sample z-test for proportions
D. A one sample z confidence interval for proportions
E. A Matched pairs t test for means
F. A two sample t test for means
G. A two sample t confidence interval for means
H. A two-sample z test for proportions
I. A two-sample z confidence interval for proportions
J. Analysis of Variance (ANOVA)
A Matched pairs t confidence interval for means
An herbal supplements company claims their sleep aid supplement is successful at putting 74% of its users to sleep within a half hour of taking the supplement. Believing the claim overstated the effectiveness of the supplement, a group of doctors decided to conduct their own study to test the company’s claim. They collected a random sample of 85 patients with sleeping problems and gave them the supplement. Only 49 of the patients reported they were able to fall asleep within a half hour. What hypotheses should be used to conduct the test?
A. Ho : p = .58 versus Ha: p > .58
B. Ho : p = .58 versus Ha: p < .58
C. Ho : p = .74 versus Ha: p > .74
D. Ho : p = .74 versus Ha: p < .74
E. Ho : µ = .74 versus Ha: µ < .74
F. Ho : µ = .5 versus Ha: µ > .5
D. Ho : p = .74 versus Ha: p < .74
To detect association between the row and column variables of a two-way table, what do we examine?
A. Whether the proportions in the marginal distribution of the column variable are decreasing, increasing, or staying constant.
B. Whether the conditional distribution in a row (or a column) equals the conditional distributions of all other rows (or columns).
C. Whether the value in each cell divided by the table total equals the value in the row total divided by the table total.
D. Whether a lurking variable interacts with both the row and column variables.
Whether the conditional distribution in a row (or a column) equals the conditional distributions of all other rows (or columns).
The following scenario will be used for questions 32-36: A large technology company is experimenting with two new website designs. The company randomly selects 60 website visitors and randomly shows them one of the two website designs. The next time one of the selected visitors returns to the website, the other website design is shown to them. Analysts record the active time spent on each of the two new websites in seconds. Differences were calculated for each visitor as x1 - x2 (where x1 is time spent on test website 1, and x2 is time spent on test website 2). The mean of the differences was x̄d = 6.2 and the standard deviation of the differences was sd = 11.2.
What would be the correct null and alternative hypotheses to show that website visitors spend more time on website 1 than on website 2.
A. H0 : μd = 0 and HA : μd > 0
B. H0 : μd = 0 and HA : μd ≠ 0
C. H0 : x̄d = 0 and HA : x̄d > 0
D. H0 : μ1 - μ2 = 0 and HA : μ1 - μ2 ≠ 0
A. H0 : μd = 0 and HA : μd > 0
The following scenario will be used for questions 32-36: A large technology company is experimenting with two new website designs. The company randomly selects 60 website visitors and randomly shows them one of the two website designs. The next time one of the selected visitors returns to the website, the other website design is shown to them. Analysts record the active time spent on each of the two new websites in seconds. Differences were calculated for each visitor as x1 - x2 (where x1 is time spent on test website 1, and x2 is time spent on test website 2). The mean of the differences was x̄d = 6.2 and the standard deviation of the differences was sd = 11.2.
Assuming the appropriate conditions are met, What would be the value of the test statistic?
A. 4.288
B. 7.754
C. 2.890
D. -3.654
4.288
A matched-pairs t-test is the same as a one-sample t-test for means, our one-sample of data just happens to be differences.
True
False
True
A matched-pairs t-test is analyzing the mean difference of paired observations.
True
False
True
The standard deviations for the samples are as follows: s(unlogged) = 3.53 and s(logged) = 4.5. What statistical procedure should be used to answer the question, “Does logging significantly reduce the mean number of tree species in a plot after 8 years?”
A. Matched pairs t test for means
B. Two sample t test for means
C. One-sample t test for means
D. Two sample t test for proportions
E. Analysis of variance
F. Chi-square test for independence
Two sample t test for means
If the t-statistic is 2.63, what is the appropriate p-value for this test? (Two sample t test for means and 19 degrees of freedom)
A. 0.0043
B. 0.01
C. 0.01< p-value < 0.02
D. 0.005< p-value < 0.01
0.005< p-value < 0.01
What conditions should be checked for this procedure? (ANOVA)
A. Randomization and all expected counts should be greater than 5
B. Randomization and normality of populations
C. Randomization, normality of populations and equal sample standard deviation
D. Randomization, normality of populations and equal population standard deviation
E. Linearity, randomization, normality of populations and equal population standard deviation
Randomization, normality of populations and equal population standard deviation
The sampling distribution of p-hat is the distribution of all sample proportions calculated from all possible random samples of the same size from a population.
True
False
True
