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Week 9
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Questions in this quiz (14)
1Dr. Walters finds that students who work less than 10 hours a week have significantly higher test scores than students who work more than 10 hours a week. In order to determine the magnitude of the effect of work hours on test scores, she should calculate a(n)
- Acritical value.
- Bnull calculation.
- Cdegree of freedom.
- Deffect size.
2The expected value of t if the null hypothesis is true would
- Aequal 0.
- Bequal 1.
- Cdepend on the degrees of freedom.
- Dvary depending on the alpha level.
3When comparing two group means, the _____ refers to the number of scores free to vary once the means are known.
- Aresearch hypothesis
- Bstatistical significance
- Cdegrees of freedom
- Dnull hypothesis
4When he analyses the difference between two means, Professor Demento finds an effect size of .85 using the statistic Cohen’s d. Professor Demento can conclude
- Athe means are separated by a .85 standard deviation.
- B 85% of the effect on the dependent variable is due to the manipulation.
- C there is a correlation of .85 between the independent and dependent variable.
- Dthe results would only occur 85% of the time.
5_____ is a type of standardised effect size that indicates the _____ the independent variable’s effect on the dependent variable.
- Apoint-biserial correlation squared (or effect size r squared) / magnitude of
- BSigma / difference in
- Cpoint-biserial correlation squared (or effect size r squared) / difference in
- Dt / magnitude of
6An aviation researcher hypothesises that during final approach to land, pilots underestimate their altitude to a greater extent at night than they do during the day. This misperception of altitude often results in long and short landings where pilots fail to touch down at the designated point on the runway. To investigate this he recruits 12 professional pilots and has half (n=6) of them perform a night landing (Condition 1) and the other half (n=6) perform a daylight landing (Condition 2) in a flight simulator. The pilots were to touch down at a specific point on the runway. For each landing the researcher measured the distance from the runway target point, in meters, to where the plane actually touched down. The mean nighttime distance was 15 metres (sum of squared deviations = 64). The mean daytime distance was 11 metres (sum of squared deviations = 20). Which of the following statistical tests would be appropriate to test the researcher’s hypothesis?
- AChi-square test
- BCorrelation
- Cz-test
- Dt-test
- EF-test
7Referring to the above aviation study, what is the (approximate) pooled variance for overestimation distance in the daytime and nighttime conditions?
- A4
- B1.7
- C1.8
- D8.4
- E2.9
8Referring to the above aviation study, what is the (approximate) estimated standard error of mean difference scores?
- A2.9
- B8.4
- C1.7
- D1.8
- E2.2
9Referring to the above aviation study, what is the (approximate) t value of the observed mean difference scores?
- A8.4
- B2.4
- C1.7
- D2.2
- E1.8
10Referring to the above aviation study,using an alpha level of 5% (.05 probability), what is the two-tailed, critical value of t for this study?
- A2.571
- B1.812
- C1.960
- D2.228
- E2.179
11Referring to the results of the previous aviation study, what conclusion should the researcher come to regarding the null hypothesis?
- Areject the null hypothesis.
- Bretain the null hypothesis.
- Cwhat’s a null hypothesis?
12Based on the analysis of the previous aviation study, approximately what percentage of variance in the dependent variable is related to the independent variable?
- A87%
- B19%
- C23%
- D36%
- E60%
13Based on the analysis of the previous aviation study, what might the researcher write in the Discussion section as a conclusion of the study?
- Athe results of this study were not statistically significant
- Bthe results of this study were inconclusive
- Cpilots are more precise when landing at night than in daylight
- Dpilots are equally precise when landing in daylight and at night
- Epilots are more precise when landing in daylight than at night
14Referring to the above aviation study, suppose one of the pilots in the nighttime condition became ill during the study and had to withdraw from the experiment. Could the researcher proceed with the same statistical analysis? If so, what would be the degrees of freedom associated with the critical test statistic?
- ANo, cannot be determined
- BThe experiment is ruined!
- CNo, 9
- DYes, 9
- EYes, 12
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- Quiz on Week 9, created by ashleighdawn on 26/05/2015.
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- ashleighdawn
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