Final Session 10a

Question 1

The methods for hypothesis testing that we have learned thus far make assumptions about what

Answer 1

population distributions and their properties:

Normal distributions
Equal variances (homogeneous variances) Equal covariances (homogeneous covariances)

Question 2

what are the parametric tests

Answer 2

test, t-test, and F ratios from one-way (between or repeated

measures) and two-way ANOVAs

Question 3

The mean and variance are sufficient to describe what

Answer 3

the shape and location of normal distributions

Question 4

For a normal distribution, the mean and variance are called what

Answer 4

parameters

Question 5

Statistical tests that assume a distribution and use parameters are calledwhat

Answer 5

parametric tests

Question 6

Statistical tests that do not assume a distribution or use parameters are called what

Answer 6

nonparametric tests

Question 7

what is another name for nonparametric tests

Answer 7

distribution-free tests

Question 8

Nonparametric tests make few assumptions or restrictions on the data. They can be used when what

Answer 8

assumptions underlying parametric tests are questionable

For example, non-normal data

Question 9

10 dieters following Atkins diet
10 dieters following Jenny Craig diet Hypothetical result:
Atkin’s group lost an average of 34.5 lbs J. Craig group lost an average of 18.5 lbs
Conclusion: Atkin’s diet is better?

what kind of data is this

Answer 9

Non-normal data

Question 10

when to use non parametric tests

Answer 10

Can be classified according to the following criteria:

The level of measurement (nominal, ordinal)
Which information is used (frequency, sign or rank) Independent or dependent samples
The number of groups to be compared (k = 1, 2, … or more)

and: There is at least one nonparametric test that could be used instead of an equivalent parametric test

Question 11

Many non-parametric tests are precursors to. ..

Answer 11

Robust” analysis techniques

Question 12

In almost every chapter in Field (your textbook) there is some mention of a robust method
These “robust” methods are good or bad?

Answer 12

typically still perform well even under assumption violations

Question 13

A (Pearson) chi-square statistic (χ2) can be used for testing what

Answer 13

independence of nominal variables

Question 14

what is independence

Answer 14

When variables are not associated

Scores on one variable do not depend on scores on the other

Question 15

A (Pearson) chi-square statistic (χ2)

The data for this test are arranged in the form of a table called a what

Answer 15

contingency table

Question 16

Prior assumptions/requirements: of Chi-Square (χ2) test

Answer 16

Random samples
Independent observations
A sufficiently large sample size is required (usually > 20) Average cell frequency should be ≥ 5

Question 17

what are the hypotheses for Chi-Square (χ2) test

Answer 17

H0: Two (nominally scaled) variables are statistically independent (no association) in the population
H1: The two variables are not independent (association) in the population
In many nonparametric procedures, the null hypothesis under the test is formulated in a more general form because either no parameters (e.g., means) are specified to be compared, or writing the hypotheses in terms of some numerical quantities would require much more notation

Question 18

what does Chi-Square as a test of independence compare

Answer 18

Compares observed and expected
frequencies
(Ogj − Egj )2 ≈ squared
deviations between observed responses and the model

Question 19

what is the model

Answer 19

Expected frequencies are

computed as if the two variables were independent

Question 20

expected frequencies are computed how for Chi-Square as a test of independence

Answer 20

as if the 2 variables were independent

Question 21

how to calculate df of Chi-Square

Answer 21

df = (a − 1)(b − 1)

Question 22

If the observed value of χ2 is greater than or equal to the critical value with df = (a − 1)(b − 1) at α = .05, we may______ the null hypothesis of independence2

Answer 22

reject

Question 23

Alternatively, if the p-value of the observed value of χ2 is less than or equal to α, we may_____ the null hypothesis

Answer 23

reject