Unit 4

Question 1

The standard error of the mean (σX̅)

Answer 1

a function of standard deviation and sample size

Question 2

Confidence Intervals

Answer 2

Range of sample data to determine a range of population means that are NOT significantly different from the sample mean

Question 3

Point Estimate

Answer 3

a single value obtained directly from the sample data (i.e., the mean)

Question 4

Interval Estimate

Answer 4

Range of sample data that we suspect (with a degree of confidence) within which the population mean resides

Question 5

Confidence Interval (CI)

Answer 5

Range of scores with specific boundaries (confidence limits), that should contain the population mean

Question 6

How to develop a confidence interval (CI)?

Answer 6

Capture 95% of the area under the “normal” distribution
This occurs at a standard deviation (z) of + 1.96.
Find: sample mean, and standard error of the mean

Question 7

What happens if a sample size is small?

Answer 7

• Usually performed with samples smaller than 30
• Use the t-distribution, not z-distribution

Question 8

Variability _______ with _______ sample sizes

Answer 8

Decreases, Larger

Question 9

What does t-distribution depend on?

Answer 9

Sample size

Question 10

Hypothesis

Answer 10

“a declarative statement that predicts that relationship between the independent and dependent variables, specifying the population will be studied.”

Question 11

Research Hypothesis

Answer 11

states the researcher’s true expectation of results guiding the interpretation of outcomes and conclusions

Question 12

Null (statistical) hypothesis - H0

Answer 12

proposes that there is no difference between certain characteristics of a population or data-generating process.

Question 13

Alternative Hypothesis - H1 (HA)

Answer 13

one that states there is a statistically significant relationship between two variables

Question 14

What is a research hypothesis?

Answer 14

Based on the physiology of aging, intelligence measurements, etc.

Question 15

Sample size affecting a statistical power:

Answer 15

tighter distribution….. decrease β, increase power

Question 16

Smaller sample size affecting a statistical power:

Answer 16

wider distribution……. Increase β, increase power

Question 17

Variability : large σ affecting statistical power

Answer 17

wider distribution of scores… will decrease statistical power

Question 18

Variability : Small σ affecting statistical power

Answer 18

tighter distribution of scores… will increase statistical power

Question 19

What is “statistical testing”?

Answer 19

• Using established statistical “tests” (i.e., equations), to determine the acceptance or rejection of a null hypothesis

Question 20

What is a “

Answer 20

the difference between a raw score and the group (sample) mean divided by the standard deviation

Question 21

What is the one-sample z-test?

Answer 21

Determining if a sample is representative of the population

Question 22

Example of one-sample z-test:

Answer 22

Example: is the average salary of Toronto Raptors players different from all NBA players?