T Test Jeopardy

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Name that Statistical Test

Let’s do research!

Fun with SPSS

Right or Wrong?

Hodgepodge

Final Jeopardy

QuestionAnswer

FINAL JEOPARDY

• ANSWER: In SPSS, this number represents the exact probability of obtaining the result you did merely by chance (AKA if the H0 is assumed to be true)

• QUESTION: What is the significance level or p-value reported under the column Sig.(2-tailed) in SPSS?

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Name that Statistical Test100

• ANSWER: An instructor tries a new method of teaching statistics using humor in one section and the old method in another. This is the type of research design she is using, and this is the type of t test she would do to evaluate her research question.

• QUESTION: What is a between-subjects design and an independent-samples t test?

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Name that Statistical Test 200

• ANSWER: A researcher wants to know if his sample’s political orietation (rated by Ps on a 9-point Likert scale from “very conservative” to “very liberal”) is significantly different from moderate (5 on the scale).

• QUESTION: What is a single-group design and a one-sample t test?

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Name that Statistical Test300

• ANSWER: A clinical psychologist compares her clients general level of functioning (assessed by the Global Assessment of Functioning [GAF] scale; Axis V of the DSM-IV-TR, 2000) before therapy and then again after 10 sessions.

• QUESTION: What is a repeated measures design and a paired-samples t test?

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Name that Statistical Test400

• ANSWER: A cognitive psychologist compares memory for nonsense syllables for participants who are either instructed in the use of a mnemonic strategy or who are not given any strategy. He is only interested in if the mnemonic strategy improves memory.

• QUESTION: What is a between-subjects design and a one-tailed independent-samples t test?

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Name that Statistical Test500

• ANSWER: A school psychologist matches students who are similar to one another on math ability and then assess performance of the two groups of students after one group participates in a special math program.

• QUESTION: What is a matched-samples research design and a paired-samples t test?

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• ANSWER: You find a significant result, but your not sure whether the difference is big enough to be important so you decide to calculate this.

• QUESTION: What is effect size or Cohen’s d?

Let’s do research!100

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Let’s do research!200

• ANSWER: A friend of your in methods calculate’s Cohen’s d and gets a result of d = 2.75. He is not sure what this means, so this is how you tell him to interpret it.

• QUESTION: What is Holy shit!! That’s a huge effect!!?

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Let’s do research!300

• ANSWER: This is when calculating Cohen’s d is appropriate.

• QUESTION: What is when you are doing a paired-samples or independent-samples t test, and the difference is significant?

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Let’s do research!400

• ANSWER: Oh no, Levene’s test is significant!! This is what it means, and this is what I should do now.

• QUESTION: What is conclude that the homogeneity of variance assumption for the independent-samples t test is violated and report t value and p value for the second row (“equal variances not assumed”)?

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Let’s do research!500

• ANSWER: In APA style, you should always report all of these things.

• QUESTION: What are means, standard deviations, degrees of freedom, obtained t value, p value, and Cohen’s d when appropriate?

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Fun with SPSS100

• ANSWER: In SPSS, the probability that you would use to evaluate significance when α = .01, and you are performing a one-tailed test.

• QUESTION: What is .01 * 2 = .02?

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Fun with SPSS200

• ANSWER: In a one-sample t test, the confidence interval for these data.

• QUESTION: What is CI: .77 ≤ µ ≤ 1.17?

One-Sample Test

4.728 29 .000 .46874 .2660 .6715disbst df Sig. (2-tailed)

MeanDifference Lower Upper

95% ConfidenceInterval of the

Difference

Test Value = .5

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Fun with SPSS300

• ANSWER: In an independent-samples t test, the row from which you report results when Levine’s test is not significant.

• QUESTION: What is “equal variances assumed”?

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Fun with SPSS400

• ANSWER: In an independent-samples t test, the confidence interval for the SPSS output reported above.

• QUESTION: What is CI: .33 ≤ µ ≤ 3.98?

Independent Samples Test

49.566 .000 3.025 34 .005 2.15584 .71279 .70728 3.60441

2.522 15.044 .023 2.15584 .85494 .33406 3.97763

Equal variancesassumed

Equal variancesnot assumed

I am active in one ormore studentorganization on campus.

F Sig.

Levene's Test forEquality of Variances

t df Sig. (2-tailed)Mean

DifferenceStd. ErrorDifference Lower Upper

95% ConfidenceInterval of the

Difference

t-test for Equality of Means

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Fun with SPSS500

• ANSWER: The conclusion a researcher would draw from these data.

• QUESTION: What is retain H0 and conclude there is no significant difference between students who prefer morning and afternoon classes?

Independent Samples Test

49.566 .000 3.025 34 .043 2.15584 .71279 .70728 3.60441

2.522 15.044 .065 2.15584 .85494 .33406 3.97763

Equal variancesassumed

Equal variancesnot assumed

I am active in one ormore studentorganization on campus.

F Sig.

Levene's Test forEquality of Variances

t df Sig. (2-tailed)Mean

DifferenceStd. ErrorDifference Lower Upper

95% ConfidenceInterval of the

Difference

t-test for Equality of Means

QuestionAnswer

Right or Wrong?100

• ANSWER: The type of error that occurs when I fail to reject a false null hypothesis.

• QUESTION: What is Type II error?

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Right or Wrong?200

• ANSWER: The type of error that occurs when I reject a true null hypothesis.

• QUESTION: Type I error?

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Right or Wrong?300

• ANSWER: The more of this you have, the more likely it is that you will make a correct decision about the null hypothesis.

• QUESTION: What is power?

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Right or Wrong?400

• ANSWER: As the probability of Type II error decreases, this simultaneously increases.

• QUESTION: What is power?

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Right or Wrong?500

• ANSWER: When you increase α, the “good news” is that the probability of this kind of mistake goes down, but this comes at a price because the probability of this other kind of mistake simultaneously increases.

• QUESTION: What is Type II error and Type I error?

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Hodgepodge100

• ANSWER: The only circumstance under which using a one-tailed test is appropriate.

• QUESTION: What is when an outcome opposite to that you are predicting means exactly the same thing to you as finding there’s no difference?

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Hodgepodge200

• ANSWER: In the independent-samples t test, the assumption that the variances in the two populations you are comparing are equal.

• QUESTION: What is the homogeneity of variance assumption?

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Hodgepodge300

• ANSWER: Increasing sample size decreases this, which then increases this.

• QUESTION: What is the standard error of the estimate and power?

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Hodgepodge400

• ANSWER: In an independent-samples t test, the null and alternative hypotheses when I’m predicting that anxiety patients who get therapy will have less anxiety than those that don’t.

• QUESTION: What is H0: µtherapy - µno therapy ≥ 0 and HA: µtherapy - µno therapy < 0?

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Hodgepodge500

• ANSWER: In an independent-samples t test, this is the null hypothesis that Levine’s test evaluates.

• QUESTION: What is the null hypothesis that the variance in the two samples being compared are equal?