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PRM TUTORIAL QUESTIONS
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Perguntas do quiz (40)
1The WAIS intelligence quotient (IQ) is normally distributed with a mean of 100 and a standard deviation of 15. If an IQ between 85 and 115 is deemed normal, what percentage (approximately) of the general population would be considered normal?
- A30%
- B50%
- C70%
- D90%
2 In the four bivariate relationships given below, in terms of Pearson product-moment correlations (r), the strongest relationship is the one for which r is:
- A.69.
- B-.70.
- C-.10.
- D.01.
3In correlational analysis, skewed variables are transformed to be normally distributed because
- Athis increases the relationship between variables.
- Bthis decreases the relationship between variables.
- Cthis removes the effect of influential points.
- Dthis might invalidate the test.
4Which one of the following does not increase the power of a test of r between X and Y?
- AStandardising the scores of X and Y.
- BAdopting a larger Type I error rate ().
- CConducting a one-tailed test instead of a two-tailed test
- DIncreasing the magnitude of r.
5In clinical trials, it is ethically responsible to use a sample size that is sufficient to detect an effect but not too large as to inconvenienced the patients any longer than necessary. Which sample size should the researcher use to ensure that she has sufficient power?
- AN = 15 (power of .70)
- BN = 22 (power of .80)
- CN = 30 (power of .90)
- DN = 37 (power of .95)
6When values of X do not exactly predict values of Y, the R2 value is:
- Aless than 0.
- B0.
- Cbetween 0 and 1
- D1
7A scatterplot of the residuals is NOT used to check for:
- Anormality of distribution of errors.
- Bthe relationship between variables.
- Cthe presence of influential cases.
- Dhomogeneity of variance of errors.
8When a regression line is fitted to the data, the lack of fit is best indicated by:
- AA negative correlation coefficient.
- BA random distribution of the residuals.
- CA non-random distribution of the residuals.
- DA small unstandardised regression coefficient.
9Which case will NOT be considered an influential in a regression of Y on X?
- AA case with a mean of X and a large Y.
- BA case with a small X and a mean of Y
- CA case with a large X and a small Y.
- DA case with a mean of X and a mean of Y.
10Residual analysis is conducted in regression to:
- Aget a more significant statistical result (i.e., t value)
- Bget a higher r value.
- Creduce the influence of misrepresentative cases.
- Dreduce the sample size.
11 In multiple regression, the effect size of the prediction is given by the:
- Asquared multiple correlation coefficient
- Bsum of the individual squared correlations between the independent variables and the dependent variable.
- Csum of the squared beta coefficients.
- Dsum of the individual semi-partial correlations.
12In standard multiple regression where X1 and X2 are used to predict Y. The square of the multiple correlation (R2), is:
- Athe sum of the correlations between Y and X1 and between Y and X2.
- Bthe sum of the squared correlations between Y and X1 and between Y and X2.
- Cthe proportion of variance in Y uniquely and jointly predicted by X1 and X2.
- Dthe proportion of variance in Y uniquely predicted by X1 plus the proportion of variance in Y uniquely predicted by X2.
13The simple correlations of X1, X2, and X3 with Y are .30, .20, and .10 respectively. A multiple regression of X1 and X2 predicting Y was just statistically significant at p = .04. If X3 is added to the equation predicting Y, we cannot be confident that:
- Athe p value will decrease.
- Bthe R value will increase.
- Cthe tolerances of X1 and X2 will decrease.
- Dthe semi-partial correlations of X1 and X2 will decrease.
14In a standard multiple regression, X1, X2 and X3 were used to predict Y. The obtained F statistic had a probability of .001. The unstandardised equation of predicted Y was 0.8X1 + 0.4X2 + 0.3X3+ 0.5. The semi-partial correlations of X1, X2 and X3 were .15, .25, and .05, respectively. We can conclude that:
- AThe set of predictors did not significantly predict Y.
- BX1 is a stronger predictor of Y than X2 or X3.
- CX3 alone would not significantly predict Y.
- DX2 makes the best unique contribution to the prediction of Y.
15In a standard multiple regression of X1, X2 and X3 predicting Y, the tolerance value of X1 is the proportion of variance in X1 that is:
- Ashared with X2 and X3 but not with Y.
- Bshared with Y but not with X2 and X3.
- Cnot shared with X2 and X3
- Dshared with X2 and X3.
16In a table of intercorrelations, predictor X1 had the highest, and statistically significant, correlation with Y (the dependent variable). Which one of the following statement is FALSE?
- AIn a forward regression, X1 was not included in the final equation because its contribution was redundant to other predictors that entered the equation.
- BIn a backward regression, X1 was not included in the final equation because its contribution was redundant to other predictors that entered the equation.
- CIn a stepwise regression, X1 was not included in the final equation because its contribution was redundant to other predictors that entered the equation.
- DIn a hierarchical regression, X1 was not relevant to the hypothesis being tested.
17In a study that had collected initial weight, weight loss after training, motivation to lose weight, duration of training period, and amount of exercise, what is likely to be the dependent variable?
- AWeight loss after training
- BMotivation to lose weight.
- CDuration of training period.
- DAmount of exercise.
18In the study described in (2), which of the following regression methods would allow the most sophisticated test of a theory on weight loss?
- AMultiple regression.
- BHierarchical regression
- CStepwise regression
- DBackward regression.
19In the study described in (2), if you were select a predictor to enter in the first step, which would you select?
- AInitial weight.
- BMotivation to lose weight.
- CDuration of training period.
- DAmount of exercise.
20In a hierarchical regression predicting Y, predictors X1 and X2 as Subset A were first entered by the researcher, followed by predictors X3 and X4 as Subset B. Which one of the following statements is definitely true?
- APredictors in Subset A are not correlated with predictors in Subset B.
- BPredictors in Subset A account for more variance in Y than predictors in Subset B.
- CTotal R2 is the sum of the changes in R2 due to the entry of Subset A and Subset B.
- DTotal R2 is the sum of the squared correlations between Y and each predictor.
21Which one of the following is most likely a polytomous variable?
- AGender.
- BMarital status
- CAge
- DIncome
22A researcher collected data on religious affiliation and involvement in gambling. Religious affiliation was a polytomous variable with four categories; namely, Christian, Buddhist, Muslim, and “No religion”. Three dummy variables (0,1), called Christian, Buddhist, and Muslim, were created to represent Christian, Buddhist, and Muslim affiliations, respectively. In a stepwise multiple regression to predict gambling, Christian and Buddhist were the two predictors selected. In interpreting the effect of Christian in this regression, which one of the following statements is definitely true?
- AC tests the effect of Christian versus Buddhist on gambling.
- BC tests the effect of Christian versus Buddhist and Muslim on gambling.
- CC tests the effect of Christian versus Muslim and “No religion” on gambling.
- DC tests the effect of Christian versus “No Religion” on gambling.
23The external validity of an experiment can be improved by:
- Ausing a representative sample of the population.
- Bholding constant the effect of nuisance variables
- Cbalancing effects of nuisance variables
- Drandom assignment of participants to treatment groups
24Balancing nuisance factors (e.g., sex, age) neutralizes their potential effects on the internal validity of an experiment, but nuisance factors can still
- Adecrease sensitivity and increase external validity
- Bdecrease both sensitivity and external validity.
- Cincrease sensitivity and decrease external validity.
- Dincrease both sensitivity and external validity.
25The defining characteristic of a true experiment is:
- Athe high degree of control in testing.
- Bthe random assignment of subjects to experimental and control conditions.
- Cthe operationalisation of dependent variables.
- Dthe systematic manipulation of independent variables.
26A sample of 100 participants were randomly allocated into two equal-sized weight loss programmes - one that focussed on dieting and the other that focussed on exercise. At the end of 20 weeks of training, 32 participants remained – 20 in the dieting group and 12 in the exercise group. Results show that the weight lost by the dieting group was significantly less than that of the exercise group. A criticism of this experiment is that the findings may be biased by the effect of:
- Ahistory
- Bselection bias
- Cattrition
- Dregression to mean
27Use of a control group, plus random assignment of participants to treatment, would allow us to avoid:
- Aselection bias
- Battrition
- Cexperimenter bias
- Deffects arising from testing
28The ANOVA tests for differences between
- Avariances of groups
- Bstandard deviations of groups
- Cmeans of groups
- Dindividuals of the groups
29A statistically significant result means that the obtained probability (p) of the test statistic is
- Aless than .05
- Bequal to .05
- Cgreater than .05
- Dgreater than 1
30If assumptions of the ANOVA are violated, the actual Type I error rate will
- Agreater than a
- Bequal to a
- Csmaller than a
- Dsmaller or greater than a
31A Brain Training software company claims that its 20-week training programme can increase a person’s IQ by five points. Given that the normative mean of IQ is 100, with a standard deviation of 15, the magnitude of the claimed effect is
- Anegligible
- Bsmall
- Cmedium
- Dlarge
32Upon obtaining a significant F test result in an ANOVA comparing mean weekly gambling frequency of Catholics, Protestants and Non-Christians, what test(s) would you use to compare the group means?
- Athe Student t-test.
- Bthe Student-Newman-Keuls test.
- Cthe Tukey HSD test.
- Dthe Tukey-Kramer test.
33Planned orthogonal contrasts should be used :
- Aset wise comparison of means
- Bpairwise comparison of means
- Cfollowing a significant F in the one-way ANOVA
- Din place of the overall F test in ANOVA
34The most conservative pairwise comparison between a set of four means is:
- Athe t-test
- BScheffe test
- CSNK test
- DTurkey
35In a conventional experiment involving five planned comparisons, the Bonferroni method would have set the error rate to:
- A<.01
- B.01
- C<.05
- D.05
36Which of the following statements about a set of orthogonal contrasts between five groups is FALSE?
- AThe coefficients of a linear contrast sum to 0.
- BThe cross-products of coefficients of any pair of contrasts sum to 0.
- CThere can, at most, be five contrasts in the set of orthogonal contrasts.
- DThere are more than one set of orthogonal contrasts
37In between-subjects ANOVA, the error term is the unexplained variance of the dependent variable. A second factor when included in a one-way ANOVA, making it a two-way ANOVA, has the effect of:
- Acontrolling another source of variance, and increasing the error term.
- Bcontrolling another source of variance, and decreasing the error term.
- Cadding another source of variance, and increasing the error term.
- Dadding another source of variance, and decreasing the error term.
38In a two-way ANOVA, the number of possible F ratios is:
- A4
- B3
- C2
- D1
39When a significant F ratio is found for interaction in ANOVA of two factors (A and B) the next step is to test:
- Amain effect of factor A.
- Bmain effect of factor B
- Csimple main effects of A and B.
- Dassociation of A and B.
40A researcher performed a two-way between-subjects ANOVA - the p value obtained for the first factor (AGE) was .02, the p value obtained for the second factor (GENDER) was .06 and the p value for the interaction (AGE x GENDER) was .04. The most appropriate conclusion to make at this point, without further testing, is:
- AAGE is statistically significant and GENDER is not statistically significant.
- BAGE is statistically significant under some level of GENDER.
- CGENDER is statistically significant under some level of AGE.
- D(B) or (C), or both.
Informações
- Descrição
- Quiz sobre PRM TUTORIAL QUESTIONS , criado por Katie Garth em 06-06-2018.
- Autor
- Katie Garth
- Idioma
- English
- Visualizações
- 5
- Histórico
- Criado em 6 jun 2018 · atualizado em 6 jun 2018
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