T-Test and Anova

Question 1

If 2 sets of data are completely separate, what would we do to compare them?

Answer 1

• Complete a Spearman (p) correlation or Pearson(r) correlation to see if they are RELATED positively or negatively
• Determine the coefficient of determination by squaring the correlation (p^2 or r^2)

Question 2

If 2 sets of data are of the same parameter but for 2 independent groups, what would we do to compare them?

Answer 2

Conduct an independent t-test to determine if there is a significant difference between the means of the groups

Question 3

If 2 sets of data are dependent and represent the same subjects in a pre-test/post-test scenario, what would we do to compare them?

Answer 3

Conduct a dependent t-test to determine if there is a significant difference between the means of the pre and post test

Question 4

What is the t-test?

Answer 4

the statistical test to determine if there is a real difference between the means of 2 sets of scores

Question 5

What is the Null Hypothesis (Ho)?

Answer 5

• a statement that indicates that for the 2 sets of scores, the means for the test are pretty well the same
• no significant difference between the means

Question 6

When would we accept the null hypothesis?

Answer 6

• when there is no significant difference

- if the t-test value is less than the critical value from the table value

Question 7

When would we reject the null hypothesis?

Answer 7

• when there is a significant difference in the means

- if the t-test value is greater than the critical value from the table value

Question 8

Rejecting the null hypothesis is the same as …

Answer 8

accepting the alternative hypothesis (Hl)

Question 9

What is the level of significance?

Answer 9

the probability of rejecting the null hypothesis when it is true

Question 10

The most common levels of significance are…

Answer 10

.05 or .01

Question 11

A .05 level of significance means that…

Answer 11

• there is a 5% chance that you are rejecting the null hypothesis when it is true
• there is a 5% chance that our conclusion will be wrong

Question 12

Typically, we use what level of significance for physical education?

Answer 12

• p = 0.05

- maybe p = 0.01 but not that common

Question 13

What is the degrees of freedom?

Answer 13

the number of values that are free to vary in a distribution so that the mean is the same

Question 14

How is the degrees of freedom calculated in independent samples?

Answer 14

df = n1 + n2 -1

Question 15

How is the degrees of freedom calculated in dependent samples?

Answer 15

df = N - 1

Question 16

When would we use t-test for independent samples?

Answer 16

• when we want to find out if 2 groups of students differ significantly on a particular test
• we want to know if one group is superior on some particular trait (ex. strength, fitness, skill)

Question 17

In medical research, we might use what level of significance?

Answer 17

p = .001

Question 18

In social science work, we might use what level of significance?

Answer 18

p = 0.10

Question 19

What is ANOVA?

Answer 19

• analysis of variance
• a statistical technique used to determine whether there are significant differences among means of three or more sets of data

Question 20

The test statistic we calculate in ANOVA tests is the

Answer 20

F ratio (instead of the t value)

Question 21

_______ is also one of the most commonly used statistical techniques used in sport science research.

Answer 21

ANOVA

Question 22

When is independent ANOVA used?

Answer 22

• when the same test is administered to different groups
• sample groups are not related to each other
• The samples are randomly drawn from a normally distributed population
• The variances of the samples are approximately equal

Question 23

When is ANOVA for repeated measures (dependent) used?

Answer 23

administration of different treatments given to the same group of subjects.

Question 24

What would we do after we accepted or rejected the Null for ANOVA tests?

Answer 24

• if you accept the Null, you are done, do not do this

- if you reject the Null, you must do your Turkey’s Honestly Significant Difference (HSD) test

Question 25

If your HSD is 1.595655, this means that …

Answer 25

the means of the groups must differ by 1.59 to be honestly significantly different

Question 26

When is repeated measures (dependent) ANOVA used?

Answer 26

• when repeated measures are made on the same subjects
• The samples are randomly selected from a normal population
• The variances for all measurements are approximately equal