Statistics

1. A method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called

random samplinglevel of significance    hypothesis testingguessing

2. The one-sample z test is a hypothesis test used to test hypotheses

concerning a single population with a known varianceconcerning at least one population    concerning the variance in a populationall of the above

3. A professor finds that the average SAT score among all students attending his college is 1150 ± 150 (μ ± σ). He polls his class of 25 students and finds that the average SAT score is 1200. Suppose he computes a one-sample z test at a 0.05 level of significance. What is his decision? 

to reject the null hypothesisto retain the null hypothesis    to reject the null hypothesis for a two-tailed test, but to retain the null hypothesis for an upper-tailed testto reject the null hypothesis for an upper-tailed test, but to retain the null hypothesis for a two-tailed test

4. ________ allows researchers to describe (1) how far mean scores have shifted in the population, or (2) the percentage of variance that can be explained by a given variable.

significanceprobability    powereffect size

5. The ________ is an inferential statistic used to determine the number of standard deviations in a t distribution that a sample mean deviates from the mean value or mean difference stated in the null hypothesis. 

t distributiont statistic    standard errordegrees of freedom

6. State the critical value(s) for the following two-tailed t test at a 0.05 level of significance: t(∞). 

±1.645±1.96    the same as for a two-tailed z test at a 0.05 level of significanceboth ±1.96 and the same as for a two-tailed z test at a 0.05 level of significance

7. A researcher reports that the mean time it takes to complete an experimental task is 1.4 ± 8.0 (M ± SD) seconds. If the null hypothesis was that the mean equals 1.0, then what is the effect size for this test using estimated Cohen's d? 

d = 0.05; small effect size

d = 0.50; medium effect size

    

d = 1.05; large effect size

There is not enough information to answer this question.

8. Computing a two-independent sample t test is appropriate when 

different participants are assigned to each groupthe population variance is unknown    participants are observed one timeall of the above

9. A researcher has participants rate the likability of a sexually promiscuous person described in a vignette as being male 

(n = 20)

 or female 

(n = 12).

 The mean likability ratings in each group were 4.0. If the null hypothesis is that there is no difference in likability ratings, then do likability ratings differ at a 0.05 level of significance? 

Yes, this result is significant, p < 0.05.

No, this result is not significant, t(30) = 0.

    

No, this result is not significant, t(30) = 1.00.

There is not enough information to answer this question, because the variance in each sample is not given.

10. A type of related samples design in which participants are observed more than once is called a 

repeated measures designmatched pairs design    matched samples designboth matched pairs design and matched samples design

11. A researcher records the level of attention among 18 students during an interactive and lecture portion of a single class. If she computes a related samples t test at a 0.05 level of significance (two-tailed test), then what is the critical value for this test? 

±1.734±1.740    ±2.110±2.101

12. A researcher computes the mean difference in locomotion in a sample of 12 rats before and 30 minutes after an injection of amphetamine. Rats were placed in a box with infrared beams. The number of times rats crossed the beams was used as a measure of locomotion. The mean difference in locomotion was 

6.2 ± 8.4 (MD ± SD),

 and this difference was significant. What is the effect size for this result using estimated Cohen's d? 

d = 0.74 (medium effect)d = 1.36 (medium effect)    d = 0.74 (large effect)d = 1.36 (large effect)

13. A researcher reports with 90% confidence that 31% to 37% of Americans believe in ghosts. What is the point estimate for this interval?

31%34%    37%31% to 37%

14. In a sample of 20 participants, a researcher estimates the 95% CI for a sample with a mean of 

M = 5.4

 and an estimated standard error 

(SM)

 of 1.6. What is the upper confidence limit for this interval? 

2.13.8    7.08.8

15. Two types of estimation are point estimation and interval estimation.

TrueFalse