RDS Final
How much variance has been explained by a correlation of r = .50? A 10% B 25% C 50% D 70%
B
If the standard deviation of a distribution is 5, what is its variance? A 10 B 2.5 C 15 D 25
D
If we were to run a four-way between-groups ANOVA, how many sources of variance would there be? A 4 B 8 C 15 D 16
D
If we calculated an effect size and found it was r = .21 which expression would best describe the size of effect?
small to medium
A Type II error occurs when
We conclude that there is not an effect in the population when in fact there is.
When the between-groups variance is a lot larger than the within-groups variance, the F-value is ____ and the likelihood of such a result occurring because of sampling error is _____ A large; high B large; low C small; low D small; high
B
A distribution with positive kurtosis (leptokurtic) indicates that: A Scores are tightly clustered around the centre of the distribution B Scores are spread widely across the distribution C Scores are clustered towards the left side of the distribution D Scores are clustered towards the right side of the distribution
A
99% of z-scores lie between: A 1.96 B 2.58 C 3.29 D 1
B
Of what is p the probability?
p is the probability of observing a test statistic at least as big as the one we have if there were no effect in the population (i.e., the null hypothesis were true).
Differences between group means can be characterized as a regression (linear) model if: A The outcome variable is categorical. B The groups have equal sample sizes. C The experimental groups are represented by a binary variable (i.e. coded 0 and 1). D Differences between group means cannot be characterized as a linear model, they must be analysed with an independent t-test.
A
If two variables are significantly correlated, r = .67, then: A They share variance. B There is no unique variance. C The relationship is weak. D The variables are independent.
A
Of the following, which is the most appropriate reason to use a non-parametric test? A When the DV is measured on an ordinal scale B When you have unequal sample sizes between conditions of the IV C When the sample size is small D When you have a violation of the assumption of homogeneity of variance
A
Subsequent to obtaining a significant result from an exploratory one-way independent ANOVA, a researcher decided to conduct three t-tests to investigate where the differences between groups lie. Which of the following statements is correct? A The researcher should accept as statistically significant tests with a probability value of less than 0.016 to avoid making a Type I error. B The researcher should have conducted orthogonal contrasts instead of t-tests to avoid making a Type I error. C This is the correct method to use. The researcher did not make any predictions about which groups will differ before running the experiment, therefore contrasts and post hoc tests cannot be used. D None of these options are correct.
A
D
A psychologist was interested in whether the amount of news people watch predicts how depressed they are. In this table, what does the value 3.030 represent? A The proportion of variance in depression explained by news exposure. B The ratio of how much error there is in the model, compared to how much variability there is in depression scores. C The ratio of how much the prediction of depression has improved by fitting the model, compared to how much error still remains. D The improvement in the prediction of depression by fitting the model
A regression model in which variables are entered into the model on the basis of a mathematical criterion is known as a: A Forced entry regression B Hierarchical regression C Stepwise regression - correct D Logistic regression
B
An experiment was done to look at whether there is an effect of both gender and the number of hours spent practising a musical instrument on the level of musical ability. A sample of 30 participants (15 men and 15 women) who had never learnt to play a musical instrument before were recruited. Participants were randomly allocated to one of three groups that varied in the number of hours they would spend practising every day for 1 year (0 hours, 1 hours, 2 hours). Men and women were divided equally across groups. All participants had a one-hour lesson each week over the course of the year, after which their level of musical skill was measured on a 10-point scale ranging from 0 (you can't play for toffee) to 10 ('Are you Mozart reincarnated?'). Which of the following tests could we use toanalyse these data? A t-test B Two-way independent ANOVA C Three-way independent ANOVA D Two-way repeated-measures ANOVA
B
Children can learn a second language faster before the age of 7'. Is this statement: A A two-tailed hypothesis B A one-tailed hypothesis C A non-scientific statement D A null hypothesis
B
What is the Jonckheere-Terpstra test used for? A To test whether the variances in your data set are approximately equal B To test for an ordered pattern to the means of the groups you're comparing C To test for an ordered pattern to the medians of the groups you're comparing D To control for the familywise error rate
C
Which of the following statements about the chi-square test is false? A The chi-square test is used to quantify the relationship between two categorical variables B The chi-square test can be used to check how well a model fits the data C In some circumstances the chi-square test can be used on continuous variables D The chi-square test is based on the idea of comparing the frequencies you observe in certain categories to the frequencies you might expect to get in those categories by chance
C
The table below contains scores from six people on two different scales that measure attitudes towards reality TV shows. Attitudes towards watching reality tv 3 7 4 1 8 6 The General reality TV scale Using the scores above, the two scales are likely to:2 5 3 1 7 7 Using the above scores, the two scales are likely to?
Correlate positively?
An experiment was conducted to see how people with eating disorders differ in their need to exert control in different domains. Participants were classified as not having an eating disorder (control), as having anorexia nervosa (anorexic), or as having bulimia nervosa (bulimic). Each participant underwent an experiment that indicated how much they felt the need to exert control in three domains: eating, friendships and the physical world (this final category was a control domain in which the need to have control over things like gravity or the weather was assessed). So all participants gave three responses in the form of a mean reaction time; a low reaction time meant that the person did feel the need to exert control in that domain. The variables have been labelled as group (control, anorexic, or bulimic) and domain (food, friends, or physical laws). Of the following options, which analysis should be conducted? A Analysis of covariance B Three-way independent ANOVA C Two-way repeated-measures ANOVA. D Two-way mixed ANOVA
D
In a two-way factorial design, the SSR (residual sum of squares) consists of: A Variance due to the independent variables and their interaction B Variance due to the independent variables, dependent variable(s) and error variance C Variance accounted for by the interaction only D Variance which cannot be explained by the independent variables
D
The assumption of homogeneity of variance is met when: A The variance is the same as the interquartile range. B The variance across groups is proportional to the means of those groups. C The variances in different groups are significantly different. D The variances in different groups are approximately equal.
D
What is the non-parametric equivalent of a one-way repeated measures ANOVA? A Wilcoxon sign test B Mann-Whitney U test C Kruskall-Wallis test D Friedman test
D
Which of the following statements about the t distribution is correct? A It is skewed. B In small samples it is narrower than the normal distribution C It follows an exponential curve. D As the degrees of freedom increase, the distribution becomes closer to normal.
D
Which of the following tests is based on calculating the difference between two sets of scores, making a note of the sign of the difference (positive or negative) and then ranking the differences from lowest to highest ignoring whether they are positive or negative? A Mann-Whitney U test B Dependent t C Wilcoxon rank-sum test D Wilcoxon signed-rank test
D
T or F: The power of a test is the probability that a given test is reliable and valid
F
In general, as sample size increases, what happens to the confidence interval?
The confidence interval gets narrower
What is the null hypothesis for the following question: Is there a relationship between heart rate and the number of cups of coffee drunk within the last 4 hours?
There will be no relationship between heart rate and the number of cups of coffee drunk within the last 4 hours.
One advantage of repeated measures designs over independent designs is that we are able to calculate a degree of error for each effect, whereas in an independent design we are able to calculate only one degree of error: true or false?
True
A psychologist was interested in whether the amount of news people watch (minutes per day) predicts how depressed they are (from 0 = not depressed to 7 = very depressed). What does the standardized beta tell us in the output? A As news exposure increases by 1 standard deviation, depression decreases by 0.224 of a standard deviation. B As news exposure decreases by 0.224 standard deviations, depression increases by 1 standard deviation. C As news exposure increases by 1 minute, depression decreases by 0.224 units. D As news exposure decreases by 0.224 minutes, depression increases by 1 unit.
A
A test statistic with an associated p value of p = .002 tells you that: A The statistical power of your test is large B The probability of getting this result by chance is 0.2%, assuming the null hypothesis is correct C The effect size of this finding is large D All of the above
B
A Pearson's correlation coefficient of -.5 would be represented by a scatterplot in which: A The data cloud looks like a circle and the regression line is flat. B There is a moderately good fit between the regression line and the individual data points on the scatterplot. C The regression line slopes upwards. D Half of the data points sit perfectly on the line.
B
The coefficient of determination: A Is the square root of the variance. B Is the square root of the correlation coefficient C Indicates whether the correlation coefficient is significant. D Is a measure of the amount of variability in one variable that is shared by the other.
D
A type I error occurs when
The results indicate a statistically significant difference when in reality no significant difference exist
A researcher testing the effects of two treatments for anxiety computed a 95% confidence interval for the difference between the mean of treatment 1 and the mean of treatment 2. If this confidence interval includes the value of zero, then she she cannot conclude that there is a significant difference in the treatment means: true or false
True
A researcher runs a single t test and obtains a p value of p = .04. The researcher rejects the null hypothesis and concludes that there is a significant effect of the experimental manipulation in the population. Which of the following are possible? A The researcher may have made a type 1 error B The researcher may have made a type 2 error C The researcher may have made a familywise error D All of the above are possible
A
An experiment was done to look at the positive arousing effects of imagery on different people. A sample of statistics lecturers was compared against a group of students. Both groups received presentations of positive images (e.g., cats and bunnies), neutral images (e.g., duvets and light bulbs), and negative images (e.g., corpses and vivisection photographs). Positive arousal was measured physiologically (high values indicate positive arousal) both before and after each batch of images. The order in which participants saw the batches of positive, neutral and negative images was randomized to avoid order effects. It was hypothesized that positive images would increase positive arousal, negative images would reduce positive arousal and that neutral images would have no effect. What technique should be used to analyse these data? A Three-way mixed ANOVA B Two-way mixed ANOVA C Three-way repeated-measures ANOVA D Two-way mixed analysis of covariance
A
An independent t-test is used to test for: A Differences between means of groups containing different entities when the sampling distribution is normal, the groups have equal variances and data are at least interval. B Differences between means of groups containing different entities when the data are not normally distributed or have unequal variances. C Differences between means of groups containing the same entities when the data are normally distributed, have equal variances and data are at least interval. D Differences between means of groups containing the same entities when the sampling distribution is not normally distributed and the data do not have unequal variances.
A
Imagine you compare the effectiveness of four different types of stimulant to keep you awake while revising statistics using a one-way ANOVA. The null hypothesis would be that all four treatments have the same effect on the mean time kept awake. How would you interpret the alternative hypothesis? A At least two of the stimulants will have different effects on the mean time spent awake. B All four stimulants have different effects on the mean time spent awake. C All stimulants will increase mean time spent awake compared to taking nothing D None of the above
A
In a one-way independent ANOVA with 40 participants and 5 conditions of the IV, what are the degrees of freedom for the between-groups Mean Squares (MSbetween)? A 4 B 5 C 35 D 40
A
In multiple regression, a high VIF statistic, a low tolerance statistic, and substantial correlations between predictor variables, ALL indicate: A Multicollinearity B Heteroscedasticity C The presence of outliers D Non-normality of the residuals
A
Non-parametric tests are used when: A The assumptions of parametric tests have not been met B You want to increase the power of your experiment C You have more than the maximum number of tied scores in your data set D All of these
A
What are the two main reasons for including covariates in ANOVA? A To reduce within-group error variance and to eliminate confounds B To increase within-group error variance and to reduce between-group error variance C To increase within-group error variance and to correct the means for the covariate D To increase between-group variance and to reduce within-group error variance
A
What does a significant test statistic tell us? A That the test statistic is larger than we would expect if there were no effect in the population. B The null hypothesis is false. C There is an important effect. D All of the above.
A
When conducting a loglinear analysis, if our model is a good fit of the data then the goodness-of-fit statistic for the final model should be: A Non-significant (p should be bigger than .05) B Significant (p should be smaller than .05) C Greater than 5 D Less than 5 but greater than 1
A
When conducting a repeated-measures ANOVA which of the following assumptions is not relevant? A Homogeneity of variance B Sphericity C Independent residuals D They are all relevant
A
Which of the designs below would be best suited to ANCOVA? A Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group. Their baseline levels of stress were measured before treatment, and again after 3 months of weekly therapy sessions. B Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group. Their levels of stress were measured and compared after 3 months of weekly therapy sessions. C Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group. The researcher was interested in the relationship between the therapist's ratings of improvement and stress levels over a 3-month treatment period. D Participants were allocated to one of two stress management therapy groups, or a waiting list control group based on their baseline levels of stress. The researcher was interested in investigating whether stress after the therapy was successful partialling out their baseline anxiety.
A
Which of the following best describes the relationship between sample size and significance testing? A In large samples even small effects can be deemed 'significant'. B In small samples only small effects will be deemed 'significant'. C Large effects tend to be significant only in small samples. D Large effects tend to be significant only in large samples
A
Which of the following statements about the t-statistic in regression is not true? A The t-statistic is equal to the regression coefficient divided by its standard deviation B The t-statistic tests whether the regression coefficient, b, is significantly different from 0 C The t-statistic provides some idea of how well a predictor predicts the outcome variable D The t-statistic can be used to see whether a predictor variables makes a statistically significant contribution to the regression model
A
A
A consumer researcher was interested in what factors influence people's fear responses to horror films. She measured gender and how much a person is prone to believe in things that are not real (fantasy proneness). Fear responses were measured too. In this table, what does the value 847.685 represent? A The residual error in the prediction of fear scores when both gender and fantasy proneness are included as predictors in the model. B The improvement in prediction of fear resulting from including both gender and fantasy proneness as predictors in the model. C The improvement in prediction of fear resulting from adding fantasy proneness to the model. D The reduction in the error in predicting fear scores when fantasy proneness is added to the model.
If the scores on a test have a mean of 28 and a standard deviation of 3, what is the z-score for a score of 34? A 3 B 2 C -2 D -3.42
B
In a two-way ANOVA there are: A Two IVs and two DVs B Two IVs and one DV C One IV and two DVs D None of the above
B
A Pearson's correlation of -.71 was found between number of hours spent at work and energy levels in a sample of 300 participants. Which of the following conclusions can be drawn from this finding? A The estimate of the correlation will be imprecise. B There was a strong negative relationship between the number of hours spent at work and energy levels. C Spending more time at work caused participants to have less energy. D Amount of time spent at work accounted for 71% of the variance in energy levels.
B
A nutritionist was interested in the effectiveness of two of the latest fad diets. The nutritionist took 30 people who wanted to lose weight and allocated them to either the SuperScienceMaxPro weight loss regime, or the SensiNutriPlus diet. He recorded their weight at 4 time points. (The start of the diet, and then every month after that for 3 months). In addition, the nutritionist was interested in whether males and females would differ in recorded weight loss over the 4 time points. What is the design of this study? A Two factorial with one independent factor and one repeated measures factor B Three-factorial with two independent factors and one repeated measures factor C Three-factorial with one independent and two repeated measures factors D Four-factorial with two independent factors and 4 repeated measures factors
B
An experiment was done to look at whether different relaxation techniques could predict sleep quality better than nothing. A sample of 400 participants were randomly allocated to one of four groups: massage, hot bath, reading or nothing. For one month each participant received one of these relaxation techniques for 30 minutes before going to bed each night. A special device was attached to the participant's wrist that recorded their quality of sleep, providing them with a score out of 100. The outcome was the average quality of sleep score over the course of the month. Which test could we use to analyse these data? A Regression only B Regression or ANOVA C ANOVA only D Chi-square
B
If predictor X shows a correlation coefficient of -.45 with outcome Y, we can confidently say that: A X is a significant predictor of Y B Variance in X accounts for 20.25% (that's -.45²) of the variance in Y C X has a causal relationship with Y D All of the above
B
The correlation between two variables A and B is .12 with a significance of p < .01. What can we conclude? A That variable A causes variable B. B That there is a small relationship between A and B. C That there is a substantial relationship between A and B. D All of the above
B
What is multicollinearity? A When predictor variables have a linear relationship with the outcome variable B When predictor variables correlate very highly with each other C When predictor variables are correlated with variables not in the regression model D When predictor variables are independent
B
What is the parametric equivalent of the Wilcoxon signed-rank test? A The independent t-test B The paired samples t-test C Independent ANOVA D Pearson's r correlation
B
A Mixed ANOVA design would be appropriate for which of the following situations? A Different participants are tested in each condition B All participants are tested in all conditions C Participants are tested in all conditions for at least one IV, and different participants are tested in each condition for at least one IV D None of the above
C
Are directional hypotheses possible with chi-square? A Yes, but only when your sample is greater than 200 B Yes, but only when there are 12 or more degrees of freedom C Yes, but only when you have a 2 × 2 design D Directional hypotheses are never possible with the chi-squared test
C
In a multiple regression model, the t test statistic can be used to test: A Differences between group means B The significance of the overall model C The significance of the regression coefficients for each predictor D The t test statistic is not used in multiple regression
C
Other things being equal, compared to the paired-samples (or dependent) t-test, the independent t-test A Has more power to find an effect. B Has the same amount of power, the data are just collected differently. C Has less power to find an effect. D Is less robust.
C
The following are all commonly stated assumptions/requirements for using ANOVA. Which of the 4 is the only one that the procedure always requires? A Subjects are assigned to treatment conditions / groups using random allocation B Data is from a normally distributed population C DV is continuous (interval or ratio) D Variance in each experimental condition is similar (assumption of homogeneity of variance)
C
Two-way ANOVA is basically the same as one-way ANOVA, except that: A The model sum of squares is partitioned into two parts B The residual sum of squares represents individual differences in performance C The model sum of squares is partitioned into three parts D We calculate the model sum of squares by looking at the difference between each group mean and the overall mean
C
Two-way repeated-measures ANOVA compares: A Two means when there are more than two independent variables, and the same entities have been used in all conditions. B Several means when there are two independent variables, and the same entities have been used in some of the conditions. C Several means when there are two independent variables, and the same entities have been used in all conditions. D Several means when there are more than two independent variables, and some have been manipulated using the same entities and others have used different entities.
C
What is the relationship between sample size and the standard error of the mean? A The standard error increases as the sample size increases. B The standard error decreases as the sample size decreases. C The standard error decreases as the sample size increases. D The standard error is unaffected by the sample size
C
When checking the assumptions of regression, what does this graph tell you? ( a p-p plot of regression standardized residual, expected vs observed) A Linearity B Homoscedasticity C Normality of residuals D Multicollinearity
C
Which of the following is an assumption of a one-way repeated measures ANOVA but not a one-way independent ANOVA? A Homogeneity of variance B Homogeneity of regression slopes C Sphericity D Multicollinearity
C
Which of the following is true about a 95% confidence interval of the mean: A There is a 0.05 probability that the population mean falls within the limits of the confidence interval. B 95 out of 100 sample means will fall within the limits of the confidence interval. C 95 out of 100 confidence intervals will contain the population mean. D 95% of the population means will fall within the confidence interval
C
Which of the following sentences best describes a covariate? A A variable that correlates highly with the dependent variable B A pair of variables that share exactly the same amount of variance of another variable in which the researcher is interested C A variable that shares some of the variance of another variable in which the researcher is interested D A variable that is not able to be measured directly
C
Which of the following sentences is an accurate description of the standard error? A It is the observed difference between sample means minus the expected difference between population means (if the null hypothesis is true). B It is the same as the standard deviation. C It is the standard deviation of the sampling distribution of a statistic. D The standard deviation squared.
C
Which of the following statements about Pearson's correlation coefficient is not true? A It varies between -1 and +1. B It can be used as an effect size measure. C It can only be used with continuous variables. D A correlation coefficient of zero indicates there is no relationship between the variables
C
With 2 × 2 contingency tables (i.e., two categorical variables both with two categories) no expected values should be below ____ A 0.8 B 1 C 5 D 10
C
A psychologist was interested in whether there was a gender difference in the use of email. She hypothesized that because women are generally better communicators than men, they would spend longer using email than their male counterparts. To test this hypothesis, the researcher sat by the computers in her research methods laboratory and when someone started using email, she noted whether they were male or female and then timed how long they spent using email (in minutes). Results of the Kolmogorov-Smirnoff test indicated a significant deviation from normality for this data, so the researcher decided to use a non-parametric test. How should she analyse the differences between males and females? A Independent t-test B Paired t-test C Wilcoxon signed-rank test D Mann-Whitney test
D
If you use a paired samples t-test: A The same participants take part in both experimental conditions. B Other things being equal, you do not need as many participants as you would for an independent samples design. C There ought to be less unsystematic variance compared to the independent t-test. D All of these are correct.
D
Imagine we conduct a one-way independent ANOVA with four levels on our independent variable and obtain a significant result. Given that we had equal sample sizes, we did not make any predictions about which groups would differ before the experiment and we want guaranteed control over the Type I error rate, which would be the best test to investigate which groups differ? A Hochberg's GT2 B Helmert C Orthogonal contrasts D Bonferroni
D
Imagine we wanted to investigate the effects of three different conflict styles (avoiding, compromising and competing) on relationship satisfaction, but we discover that relationship satisfaction is known to covary with self-esteem. Which of the following questions would be appropriate for this analysis? A What would the mean self-esteem score be for the three groups if their levels of relationship satisfaction were held constant? B Does relationship satisfaction have a significant effect on the relationship between conflict style and self-esteem? C What would the mean relationship satisfaction be if levels of self-esteem were held constant? D What would the mean relationship satisfaction be for the three conflict style groups, if their levels of self-esteem were held constant?
D
Statistics enthusiast and Dub Reggae legend 'Mad Professor' conducted a study into the effects of listening to music on a memory task. He ended up with three independent variables and one dependent variable, and he wished to analyse all possible main effects and interaction effects. How many model effects in total will he have? A 1 B 3 C 6 D 7
D
The relationship between two variables partialling out the effect that a third variable has on both of those variables can be expressed using a: A Bivariate correlation B Semi-partial correlation C Point-biserial correlation D Partial correlation
D
What is a limitation of the Chi-square test? A It cannot be used when you have more than 2 categorical variables B Directional hypotheses are not possible when you have more than two conditions of a variable C A small sample size can result in an unreliable test statistic D All of the above
D
T or F: Power is linked to the probability of making a Type II error.
T
T or F: Power is the ability of a test to detect an effect given that an effect of a certain size exists in a population.
T
T or F: We can use power to determine how large a sample is required to detect an effect of a certain size.
T