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Exam 3
Ch. 9
1. A population variance is used to calculate the ? statistic for a hypothesis test.
2. Holding everything else constant, increasing the sample size decreases standard error.
3. With ? = .01 the two-tailed critical region for a sample of ? = 20 subjects would have boundaries of ? = ±2.861.
4. To calculate a ? statistic, the value for ? or ?2 is needed.
5. A sample of n=15 scores would produce a t statistic of df=16.
Ch. 10
6. An independent-measures design could be used to evaluate the difference in verbal skills between 3-year old girls and
3-year old boys.
7. The null hypothesis for the independent-measures ? test states that there is no difference between the two population
means.
8. The homogeneity of variance assumption requires that the two samples have equal variances.
9. One sample has ? = 6 and ?? = 20, and a second sample has ? = 6 and ?? = 30. The pooled variance for the two
samples is 50/10.
10. An independent-measures study uses a separate sample to represent each of the treatment conditions or populations
being compared.
Ch. 11
11. For the scores 3, -8, 6, -4, -2, the value of MD = -1.
12. A researcher obtains a ? statistic of ? = 2.00 from a repeated measures study using ? = 17 participants. If effect size
is measured using ?2, then ?2 = 4/20 = 0.20.
13. The repeated-measures design is suited to situations in which a particular type of subject is not readily available for
study.
14. The repeated-measures design is helpful because it uses fewer subjects for two samples.
Ch. 12
15. In general, the goal of estimation is to determine how much effect a treatment has.
16. The mean for the general population of differences scores can be estimated using the repeated-measures ? statistic.
17. Compared to a point estimate, an interval estimate has less confidence but greater precision.
18. For a single sample of ? = 23, the values of ? used to construct a 90% confidence interval would be ? = ±1.717.
19. In general, as confidence increases, the precision of an interval estimate decreases.
20. For a point estimate, a value of ? = 0 is used in the estimation equation.