13.2 The t And F Tests

Question 1

The _-____ is commonly used to examine whether two groups are significantly different from each other.

Answer 1

t-test

Question 2

The _ ____ is a more general statistical test that can be used to ask whether there is a difference among three or more groups or to evaluate the results of factorial designs.

Answer 2

F test

Question 3

To use the t distribution to evaluate our data, we need to calculate the value of t from the ____ data and evaluate the ____ t in terms of the sampling distribution of t that is based on the null hypothesis.

Answer 3

obtained

Question 4

If the obtained t has a low probability of occurrence (.05 or less), then the null hypothesis is ____.

Answer 4

rejected

Question 5

The t value is a ratio of two aspects of the data, the difference between the group means and the variability within groups.

Answer 5

t = group difference / within-group variability

Question 6

The group difference is simply the difference between our obtained means; under the null hypothesis, you expect the difference to be zero.

Answer 6

Mean of first group minus mean of second group.

Question 7

The value of t ____ as the difference between your obtained sample means increases.

Answer 7

increases

Question 8

The within-group variability is the amount of variability of scores about the ____.

Answer 8

mean

Question 9

The ____ ____ and the ____ are indicators of how much scores deviate from the group mean.

Answer 9

standard deviation and the variance

Question 10

When comparing two means, you assume that the ____ of ____ are equal to n1 + n2 - 2, or the total number of participants in the groups minus the number of groups, this is called degrees of freedom.

Answer 10

degrees of freedom

Question 11

The degrees of freedom are number of scores ____ to ____ once the means are known.

Answer 11

free to vary

Question 12

A ___-____ test has a specified direction of difference between the two groups. For example, group one will be greater than group two.

Answer 12

one-tailed

Question 13

A ___-____ test does not specify a predicted direction of difference. For example, group 1 will differ from group 2.

Answer 13

two-tailed

Question 14

Whether to specify a one-tailed or two-tailed test will depend on whether you originally designed your study to test a ____ hypothesis.

Answer 14

directional

Question 15

The ____ of ____, or F test, is an extension of the t-test.

Answer 15

analysis of variance

Question 16

The _ ____ is a ratio of two types of variance: systematic variance and error variance.

Answer 16

F statistic

Question 17

____ ____ is the deviation of the group means from the grand mean, or the mean score all individuals and all groups.

Answer 17

Systematic variance

Question 18

____ ____ is the deviation of the individual scores in each group from their respective group means.

Answer 18

Error variance

Question 19

The larger the F ratio is, the more likely it is that the results are ____.

Answer 19

significant

Question 20

After determining that there was a statistically significant effect of the independent variable, researchers will want to know the magnitude of the effect. Therefore, we want to calculate them estimate of ____ ____.

Answer 20

effect size