Stats Test 1
You manager has asked you to identify the number of men responding in your annual staff survey. How would you generate this output? Open the output viewer and click on: Save As → Pie Chart Click on: Analyze → Descriptive Statistics → Frequencies Click on: Graphs → Frequencies → Pearson Open the variable viewer and recode the value labels
b
which of the following is designed to compensate for practice effects? A repeated measured design Counterbalancing A control condition Giving participants a break between tasks
b
What is the alternative hypothesis for the following question: Does eating salmon make your skin glow? Eating salmon does not predict the glow of skin. There will be no difference in the appearance of the skin of people who eat salmon compared to those who don't. People who eat salmon will have a more glowing complexion compared to those who don't. People who eat salmon will have a similar complexion to those who do not.
c
Of what is the standard error a measure? The 'flatness' of the distribution of sample scores. The variability in scores in the sample. The variability of scores in the population. The variability of sample estimates of a parameter.
d
What does the 'error bar' on an error bar chart represent? The confidence interval round the mean. The standard error of the mean. It can represent any of a, b or c
d
What is the relationship between sample size and the standard error of the mean? (Hint: The law of large numbers applies here: the larger the sample is, the better it will reflect that particular population.) The standard error increases as the sample size increases. The standard error decreases as the sample size decreases. The standard error is unaffected by the sample size. The standard error decreases as the sample size increases.
d
What type of distribution does the z-statistic follow? Discrete uniform distribution Poisson binomial distribution Degenerate distribution Normal distribution
d
Which of the following distributions is used for accepting the null hypothesis? Poisson Chi-square Binominal None of the above
d
Which of the following does a box-whisker plot not display? The range The interquartile range The lower quartile The mean
d
Which of the following is a type of histogram? Stacked histogram Frequency polygon Population pyramid All of the above
d
Which of the following terms best describes the sentence: 'In a blind tasting, people will not be able to tell the difference between margarine and butter'? A directional hypothesis An operational definition A null hypothesis A non-directional hypothesis
d
is the probability (p-value) low in relation to level of significance?
reject the null
In general, as the sample size (N) increases: The confidence interval becomes less accurate. The confidence interval gets wider. The confidence interval is unaffected. The confidence interval gets narrower.
d
as our sample size grows, it becomes normal with a large enough sample, we can use the standard error
Central Limit Theorem
A study undertaken in a surgical ward determined that the use of a specific antibacterial handwash was considered to be the most effective and cost effective. Which of the following results would be considered most significant? p < .01 p < .001 p < .0005 p < .0001
d
An independent variable is: A variable thought to predict an outcome variable An outcome Synonymous with a dependent variable A variable thought to be the cause of some effect
d
Correlational studies allow the researcher to: Test for differences between two variables. Predict the effect of one variable upon another. Make causal inferences about the relationship between two variables. Identify the relationship between two variables
d
How is a variable name different from a variable label? It is shorter and less detailed. It is longer and more detailed. It is abstract and unspecific. It refers to codes rather than variables.
d
'Sleep deprivation will reduce the ability to perform a complex cognitive task'. State the direction of this hypothesis: Directional Non-directional Both Not enough information given
a
A Type I error occurs when: (Hint: When we use test statistics to tell us about the true state of the world, we're trying to see whether there is an effect in our population.) We conclude that there is an effect in the population when in fact there is not. We conclude that there is not an effect in the population when in fact there is. We conclude that the test statistic is significant when in fact it is not. The data we have typed into SPSS is different from the data collected.
a
A café owner wanted to compare how much revenue he gained from lattes across different months of the year. What type of variable is 'month'? categorical dependent interval continuous
a
A frequency distribution in which high scores are most frequent (i.e. bars on the graph are highest on the right hand side) is said to be: Negatively skewed Leptokurtic Positively skewed Platykurtic
a
A multiple choice test to measure primary school pupils' ability in mathematics is administered to a number of pupils across Newcastle-upon-Tyne. There is a mean test score of 100 and a standard deviation of 15. Can the test score of one pupil be calculated from the z-score? Yes No Never Insufficient information
a
A sports psychologist was interested in the effects of a six-week imagery intervention on an athlete's ability to execute a sport-specific skills such penalty taking in football/soccer. How might you define the imagery variable? Independent variable Dependent variable Outcome variable Resultant variable
a
A two-tailed test is considered a: Non-directional test Directional test Uni-directional test Bi-directional test
a
Assume a researcher found that the correlation between a test she had developed and exam performance was .5 in a study of 25 students. She had previously been informed that correlations under .30 are considered unacceptable. The 95% confidence interval was [0.131, 0.747]. Can you be confident that the true correlation is at least 0.30? No you cannot, because the lower boundary of the confidence interval is .131, which is less than .30, and so the true correlation could be less than .30. Yes you can, because the upper boundary of the confidence interval is above .30 we can be 95% confident that the true correlation will be above .30 No you cannot, because the sample size was too small. Yes you can, because the correlation coefficient is .5 (which is above .30) and falls within the boundaries of the confidence interval.
a
Children can learn a second language differently before the age of 7 than after.' Is this statement: A two-tailed hypothesis A non-scientific statement A one-tailed hypothesis A null hypothesis
a
Confidence intervals are: A range within which the researcher believes the true mean value will fall Boundaries to prevent the true mean value being calculated Calculating all of the mean values of the various sample populations Limiting the number of sample populations studied
a
How is a null hypothesis denoted? H0 H1 H2 H3
a
How would you conceptualize the measurement of blood pressure from a group of individuals on multiple occasions to see if the results were sufficiently similar? Reliability Validity Similarity Predictability
a
If research suggests that the mean number of insurance quotations a person makes in a year is 26 with a standard deviation of 4, what is the z-score for a score of 18? -2 11 2 -1.41
a
Normally distributed data are normally referred to as: Bell-shaped Asymmetrical Skewed Peaked
a
Of what is p the probability? (Hint: NHST relies on fitting a 'model' to the data and then evaluating the probability of this 'model' given the assumption that no effect exists.) 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). p is the probability that the results are due to chance, the probability that the null hypothesis (H0) is true. p is the probability that the results are not due to chance, the probability that the null hypothesis (H0) is false. p is the probability that the results would be replicated if the experiment was conducted a second time.
a
Ordinal level data are characterized by: Data that can be meaningfully arranged by order of magnitude Equal intervals between each adjacent score A fixed zero None of the above
a
Variation due to variables that have not been measured is known as: Unsystematic variation Homogenous variance Systematic variation Residual variance
a
What effect would increasing the sample size have on the confidence intervals of the group? Confidence intervals would decrease in size. Confidence intervals would increase in size. Confidence intervals are unaffected by sample size. Confidence intervals could either increase or decrease in size.
a
What is the definition of 'mean square'? A sum of squares divided by its degrees of freedom The square root of the mean The square of the mean A table of means with four cells
a
Which of the following could be described as a null hypothesis for testing the link between academic attainment of secondary school pupils studying for GCSEs and hours of independent study completed by each student? The number of hours of independent study has no effect upon academic attainment. The more hours of independent study completed, the greater the academic attainment. The more hours of independent study completed, the lower the academic attainment. Independent study improves academic attainment.
a
if you were to research the effect of caffeine dose (no caffeine, high and low concentrations) on 100 m sprint time, what would be the independent variable if a repeated-measures design was to be used? Sprint time before the supplementation (i.e. pre-test) Sprint time after the supplementation (i.e. post-test) Caffeine dose A different variable
a
if the standard error is large, there is _______ (a lot/a little) of variability between means of different samples
a lot
con and solution of Between group experiments?
assignment bias and generalization
95% of data under a normal distribution curve fall between which z-scores? -1 and +1 -2 and +2 -2.5 and +2.5 -3 and +3
b
A 95% confidence interval for the difference between two population means is found to be (-0.08, 0.15). Which of the following statements is true? The probability is 0.95 that a significant difference between the population means lies between -0.08 and 0.15. We can be 95% confident that the true difference between the population means falls between -0.08 and 0.15. The probability is 0.05 that the true difference between the population means is between -0.08 and 0.15 The two populations cannot have the same means.
b
A Type II error occurs when: (Hint: This would occur when we obtain a small test statistic--perhaps because there is a lot of natural variation between our samples.) We conclude that there is an effect in the population when in fact there is not. We conclude that there is not an effect in the population when in fact there is. We conclude that the test statistic is significant when in fact it is not. The data we have typed into SPSS is different from the data collected.
b
A variable that measures the effect that manipulating another variable has is known as: An independent variable A dependent variable A confounding variable A predictor variable
b
Confidence intervals are a means of assessing the accuracy of sample data. If you read that the average expected range of birth weight of newborns in your area falls between 2 and 12 lbs, what additional information is required in order to predict a 95% confidence interval in terms of birth weights? z-score and standard error of the sample mean and standard deviations of the sample, and z-score mean and standard deviations of the sample mean and z-score of the sample
b
How would you use the drop-down menus in SPSS to generate a frequency table? Open the output viewer and click on Save As → Pie Chart Click on Analyze → Descriptive Statistics → Frequencies Click on Graphs → Frequencies → Pearson Open the variable viewer and recode the value labels
b
If a doctor wishes to study the effect of a certain type of antibiotic treatment on hospitalized patients, what type of variable will be required to allow for measurements between the group of patients given the treatment and those who are given alternative treatment? Independent variable Coding variable Dependent variable String variable
b
If my experimental hypothesis were 'Eating cheese before bed affects the number of nightmares you have', what would the null hypothesis be? Eating cheese before bed gives you more nightmares. The number of nightmares you have is not affected by eating cheese before bed. Eating cheese before bed gives you fewer nightmares. Eating cheese is linearly related to the number of nightmares you have.
b
In SPSS what would be the window that you need to access in order to enter your data for analysis? Data viewer Data editor Syntax viewer SPSS viewer
b
In SPSS, what is the data view window? A table summarizing the frequencies of data for one variable A spreadsheet into which data can be entered A dialog box that allows you to choose a statistical test A screen in which variables can be defined and labelled
b
In experiments the independent variable is manipulated to determine: Effects on the individual participants Effect on the dependent variable Effects of certain stimuli Relation to other variables
b
In your experiment (Q12) you also ask some qualitative questions to enrich the statistical data. What is the correct way to record non-numerical values in SPSS? You can't, SPSS only uses numbers, Define the variable as 'string'. Recode all the values as numbers. Define the variable as 'date'.
b
Large standard deviations will have what sort of distribution, relative to a distribution with a low standard deviation? Raised Flatter The same Zero
b
The discrepancy between the numbers used to represent something that we are trying to measure and the actual value of what we are measuring is called: Reliability Measurement error The 'fit' of the model Variance
b
The standard deviation is the square root of the: range variance sum of squares coefficient of determination
b
There are basically two types of statistics - descriptive and inferential. Which of the following sentences are true about descriptive statistics? Descriptive statistics enable you to make decisions about your data, for example, is one group mean significantly different from the population mean? Descriptive statistics describe the data. Descriptive statistics enable you to draw inferences about your data, for example does one variable predict another variable? All of the above.
b
To predict a person's occupation by their income, lawyers are coded as 0 and accountants as 1. If there are 100 cases and 40 are accountants, what is the mean of the variable? 40 0.4 2.5 25
b
Under a null hypothesis, a sample value yields a p-value of .015. Which of the following statements is true? This finding is statistically significant at the .01 level of significance. This finding is statistically significant at the .05 level of significance. This finding is not statistically significant. This finding is statistically significant at the .001 level of significance.
b
What is an outlier? A set of data outside the data file. A single score (e.g., participant response) that is very different from others. A score derived from a participant who has lied. A variable that cannot be quantified.
b
What is not an advantage of repeated-measures designs in comparison to independent-measures designs? Each participant acts as their own control. Researchers can study cross-cultural effects more easily. Researchers can study trends more easily. They require fewer participants overall.
b
What is the conventional level of probability that is often accepted when conducting statistical tests? .1 .05 .5 .001
b
What is the standard deviation? The variance squared. A measure of the dispersion or spread of data around the mean. The degree to which scores cluster at the ends of the distribution. A measure of the relationship between two variables.
b
Which of the following is true about a 95% confidence interval of the mean for a sample of grocery shoppers rating their favourite store? 95 out of 100 sample means will fall within the limits of the confidence interval. There is a 95% chance that the population mean will fall within the limits of the confidence interval. 95 out of 100 population means will fall within the limits of the confidence interval. There is a .05 probability that the population mean falls within the limits of the confidence interval.
b
If a test is valid, what does this mean? The test has internal consistency. The test will give consistent results. The test measures a useful construct or variable. The test measures what it claims to measure.
d
A null hypothesis: States that the experimental treatment will have an effect. Is rarely used in experiments. Predicts that the experimental treatment will have no effect None of the above.
c
A scatterplot shows: The frequency with which values appear in the data) The average value of groups of data) Scores on one variable plotted against scores on a second variable. The proportion of data falling into different categories.
c
Assume that for the research into stomach and lung cancer the significance value is set at p < .05 and an independent t-test yielded a significance value of p = .06. What should you do? Accept the null hypothesis and state that there is no difference in the duration of the survival between the two types of cancer. Reject the null hypothesis and state that there is a difference in the duration of the survival between the two types of cancers. Accept the null hypothesis and state that there is no difference in the duration of the survival between the two types of cancer, but that it is worth further investigation. The results are inconclusive.
c
Assuming the histogram is not normally distributed (i.e. does not have a 'bell-shaped' curve appearance), what would be the most appropriate measure of central tendency? Mean Mode Median Menial
c
If the scores on a test have a mean of 26 and a standard deviation of 4, what is the z-score for a score of 18? 2 11 -2 -1.41
c
The aim of experimental research is to: Be a phenomenon Cause a phenomenon Investigate what caused a phenomenon Prevent a phenomenon
c
The interquartile range represents how many percentiles? 25% 10% 50% 75%
c
What does the term 'familywise error rate' mean? The probability of a Type II error occurring The error rate across statistical tests conducted on different experimental data The error rate across statistical tests conducted on the same experimental data a and c
c
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? People who drink more cups of coffee will have significantly lower heart rates. People who drink more coffee will have significantly higher heart rates. There will be no relationship between heart rate and the number of cups of coffee drunk within the last 4 hours. There will be a significant relationship between the number of cups of coffee drunk within the last 4 hours and heart rate.
c
When the results of an experiment can be applied to real-world conditions, that experiment is said to have: Factorial validity Criterion validity Ecological validity Content validity
c
Which of the following is true about a 95% confidence interval of the mean: 95% of population means will fall within the limits of the confidence interval. 95 out of 100 sample means will fall within the limits of the confidence interval. 95 out of 100 confidence intervals will contain the population mean. There is a 0.05 probability that the population mean falls within the limits of the confidence interval.
c
Which of the following statements is true? Confidence intervals are known as point estimates. Confidence intervals are not biased by non-normally distributed data. If the confidence interval for the difference between two means does include zero then the difference between the means is statistically significant. Confidence intervals tell us about the range of possible values of a statistic within the sample
c
Why is the standard error important? It is unaffected by the distribution of scores. It is unaffected by outliers. It gives you a measure of how well your sample parameter represents the population value. It tells us the precise value of the variance within the population.
c
variable other than the predictor variable that may affect the outcome variable
confounding variables
does the test work?
content validity
type of research that is observed naturally, no interference
correlation
type of research where we observe may people at the same point in time
cross sectional
A frequency distribution in which there are too many scores at the extremes of the distribution said to be: Negatively skewed Leptokurtic Positively skewed Platykurtic
d
A repeated-measures design will be useful when: There are many subjects to study. The subjects are homogenous. There is a great effect in the independent variable. The participants vary greatly from one another.
d
type of research where we manipulate environments systematically with one or more variable to see the effect
experimental
model + error =
outcome
probability of observing what we observe if our null hypothesis is true
p value
con and solution of Repeated Measures experiments?
practice effects and counterbalancing
how a big group of sample means relate to the population mean (standard deviation of sample means)
standard error