Chapter 12

Question 1

Null Hypothesis Significance Testing (NHST)

Answer 1

use of statistics and probabilities to evaluate the null hypothesis

Question 2

Correlation family (or r-type)

Answer 2

category of effect size indices, including phi , point-biserial r, the alerting r, the contrast r and the effect size r

Question 3

Difference Family

Answer 3

a category of effect size indices, including Cohen’s d and the risk difference

Question 4

Ratio Family

Answer 4

a category of effect size (including the odds ratio and relative risk)

Question 5

Null Hypothesis

Answer 5

generally implies no difference in the success rate between the experimental group and the control group

Question 6

Alternative Hypothesis

Answer 6

generally implies difference in the success rate between the experimental group and the control group

Question 7

Type I Error

Answer 7

mistakenly rejecting the null hypothesis when it is intact true and should not have been rejected

Question 8

Type II Error

Answer 8

fail to reject the null hypothesis when it is false and should have been rejected

Question 9

alpha

Answer 9

probability of making a Type I error

Question 10

Significance Level

Answer 10

probability of a type I error

Question 11

p value

Answer 11

probability value or level obtained in a test of significance

Question 12

Beta

Answer 12

risk or probability of making a type II error

Question 13

Two-tailed p value

Answer 13

applicable when the alternative hypothesis did not specifically predict in which direction or (tail) of the probability distribution the significance would be detected

Question 14

One-tailed p value

Answer 14

applicable when the alternative hypothesis requires the significance to be in one tail rather than the other

Question 15

Counter null Statistic

Answer 15

useful for minimizing two common error in thinking about effect sizes

• 1st common error: researcher mistakenly infers that failure to reject the null hypothesis also implies and effect size of 0
• 2nd common error: research mistakenly equates the rejection of the null hypothesis with having demonstrated a scientifically important effect

Question 16

Statistical Power

Answer 16

the sensitivity of a significance test to provide an adequate opportunity to reject the null hypothesis when it warrants rejection

Question 17

Power Analysis

Answer 17

used to see whether there was a reasonable chance to of rejecting the null hypothesis and whether the statistical power should be increased in any future studies to increase the sensitivity of the test

Question 18

Power

Answer 18

1 - Beta

• the probability of not making a Type II Error

Question 19

Odds Ratio (OR)

Answer 19

Relative indication of the odds for a binary variable in two groups of participants

example: adverse event present vs. not present and treated subjects vs. controlled subjects

Question 20

Relative Risk (RR)

Answer 20

ratio of the incidence of a specified adverse event among participants administered a treatment to the incidence rate of such an event in the participants that were not given the treatment

Question 21

Relative Risk Reduction (RRR)

Answer 21

reduction in relative risk as a percentage

Question 22

Risk Difference (RD)

Answer 22

the difference between the risk of a specified adverse event in the treatment group and the control group

Question 23

Number needed to Treat (NNT)

Answer 23

the number of patients needed to be treated by a drug for one patient to benefit