Question 1

What is the goal of significance testing?&#10;A) To be able to reject the null hypothesis&#10;B) To be able to accept the null hypothesis&#10;C) To provide an objective, agreed upon criterion to decide whether differences are due to chance&#10;D) To provide an objective, agreed upon criterion to decide whether differences are due to the intervention

Accepted Answer

Significance testing aims to provide an objective criterion to determine if observed differences in data are likely due to chance or if they are statistically significant, implying they could be attributed to something other than random variation.

Question 2

Use of a pretest as well as a posttest, rather than a posttest by itself, is valuable because&#10;A) One can evaluate and statistically adjust for any pretest sensitization effect&#10;B) One can use a directional test to evaluate change, i.e., did patients improve&#10;C) Reduces bias due to multiple statistical tests&#10;D) The error term is reduced in the statistical test and power is increased

Accepted Answer

Using both a pretest and a posttest allows for the reduction of error variance in the statistical test, which increases the power to detect a true effect.

Question 3

How can power be augmented in an investigation?&#10;A) Through the use of posttests&#10;B) Through maintaining conventional levels of significance&#10;C) Through the use of directional tests&#10;D) Through controlling the side effects of treatment

Accepted Answer

Using directional tests can increase power by focusing on a specific direction of effect, which reduces the critical region and makes it easier to detect an effect if it exists.

Question 4

Statistical significance, magnitude of effect, and clinical significance:&#10;A) Overlap greatly and any two allows one to infer the other one&#10;B) Reflect different facets of the data and bear no necessary relation to each other&#10;C) A large effect size is likely to mean both that the effect was statistically and clinical significant&#10;D) a and b

Accepted Answer

Statistical significance, magnitude of effect, and clinical significance reflect different aspects of research findings. Statistical significance pertains to the likelihood that the observed results are due to chance, magnitude of effect refers to the size of the difference or relationship observed, and clinical significance concerns the practical importance of the effect in a clinical setting. These aspects can vary independently; for example, a statistically significant result may have a small effect size that is not clinically significant.

Question 5

What is statistical significance?&#10;A) A criterion used to determine the level of confidence of two groups differing at levels greater than chance&#10;B) A criterion used to determine the level of confidence of the null hypothesis being false&#10;C) The practical value or importance of the effect of an intervention&#10;D) A method for expressing differences between groups in a common metric

Accepted Answer

Statistical significance is a criterion used to determine if the observed difference between groups is greater than what might be expected by chance, indicating that the null hypothesis may be false.

Question 6

Intent-to-treat data analyses is designed&#10;A) To preserve the random composition of groups&#10;B) To keep the investigator from changing the hypotheses that will be studied&#10;C) To evaluate the results with those who completed the pre, treatment, and post&#10;D) Estimates data that the subject would have had from others in the same treatment condition but who completed treatment

Accepted Answer

Intent-to-treat analysis is designed to preserve the random composition of groups by including all participants who were originally allocated to each group, regardless of whether they completed the study, adhered to the intervention, or were lost to follow-up. This approach helps to maintain the comparability of groups that was achieved by the initial random assignment, thus providing a more unbiased estimate of the treatment effect.

Question 7

Which of the following is a valid method of determining the necessary sample size of an investigation?&#10;A) Through the effect size, alpha, and power&#10;B) Through the clinical significance of an investigation&#10;C) Through conventions in his or her field of research&#10;D) Through the use of significance tests

Accepted Answer

The necessary sample size is typically determined using the effect size, alpha (significance level), and power (probability of detecting an effect if there is one), which are statistical concepts used to ensure the study is adequately powered to detect meaningful effects.

Question 8

When are multivariate analyses appropriate?&#10;A) When utilizing a factorial design&#10;B) When measures are conceptually related&#10;C) When measures are uncorrelated&#10;D) When interest is in individual measures

Accepted Answer

When measures are conceptually related, multivariate analyses are appropriate because they allow researchers to examine the relationships between multiple variables simultaneously.

Question 9

What is alpha?&#10;A) A method of expressing differences between groups in a common metric&#10;B) The probability of rejecting the null hypothesis when that hypothesis is true&#10;C) The probability of rejecting the null hypothesis when it is false&#10;D) The probability of accepting the null hypothesis when it is false

Accepted Answer

Alpha, often denoted as α, is the probability of making a Type I error, which occurs when the null hypothesis is incorrectly rejected when it is actually true. This is commonly set at a threshold such as 0.05 or 5%, indicating a 5% risk of concluding that a difference exists when there is no actual difference.

Question 10

What is an advantage of meta-analysis?&#10;A) Can examine variables that were not a focus of the original research&#10;B) Can examine the relations between measures&#10;C) Can compare the validity of different investigations&#10;D) Can examine the clinical significance of investigations

Accepted Answer

Can examine variables that were not a focus of the original research

Question 11

Which of the following is an important consideration specific to making multiple comparisons?&#10;A) Controlling variability in the data&#10;B) Controlling the reliability of the measures&#10;C) Controlling the experimental-wise error rate&#10;D) Controlling the per-comparison error rate

Accepted Answer

The answer of Which of the following is an important...

Question 12

A statistically significant effect at the p < .00001 level, means&#10;A) One can reject the null hypothesis&#10;B) One can reject the null hypothesis and the investigator's hypothesis is strongly supported&#10;C) The result is statistically significant and the effect size is large&#10;D) The finding is very significant

Accepted Answer

The answer of A statistically significant effect at the p...

Question 13

What is power?&#10;A) An objection to the use of significance testing in psychological research&#10;B) The expression of differences between groups in a common metric&#10;C) The probability of accepting the null hypothesis when it is false&#10;D) The extent to which a difference can be detected when a difference exists

Accepted Answer

The answer of What is power?&#10;A) An objection to the...

Question 14

A Bonferroni adjustment is designed&#10;A) To allow one to detect effects that might be just at the borderline level e.g., p < .0 which might be important for theoretical reasons&#10;B) To control for experiment-wise error rate&#10;C) To increase power by using a more sensitive statistical test&#10;D) a and b

Accepted Answer

The answer of A Bonferroni adjustment is designed&#10;A) To allow...

Question 15

Which of the following is the most dependent on sample size?&#10;A) Validity&#10;B) Correlation coefficient&#10;C) Alpha&#10;D) Effect size

Accepted Answer

The answer of Which of the following is the most...

Deck 15: Statistical Methods of Data Evaluation