Exam 7: Examining Differences Between Means: The T-Test

In devising an interview schedule for a study that will involve interpretative phenomenological analysis (IPA), which of the following should one try to avoid?

"Uncertainty arising from variation in observations around any measure of central tendency (or other expected value)and for which the researcher proposes no explanation.It is uncertainty in knowing or predicting individual scores on the basis of a measure of central tendency.This uncertainty is quantified by dispersion measures (e.g.standard deviation, variance, range).What construct is this a glossary definition of?

If an experimenter conducts a t-test to see whether the responses of subjects in a control group differ from those of an experimental group, which of the following factors will not affect the significance of that test?

"A barrier to the correct interpretation of results that arises when the range of scores is limited because they are clustered in the region of the minimum scale value." What type of effect is this a glossary definition of?

"The hypothesis that the research reveals an effect (e.g.that two samples are drawn from different populations and that there is an informative difference between their means).Also referred to as H₁.This is normally the hypothesis that the research was designed to test." What type of hypothesis is this a glossary definition of?

After careful ethical review of planned procedures, a researcher tests a new brain activation drug by taking a sample of 50 volunteers and randomly assigning 25 participants to the treatment condition and 25 to the control (placebo)condition.She then carries out an fMRI scan to assess the level of activation in regions of the participants' brains 30 minutes after administering the drug.She carries out a between-participants t-test in SPSS which provides the output shown below: Which of the following statements is true?

"An assessment of the correspondence between an observed pattern of data and a particular model of that data." What statistical construct is this a glossary definition of?

A psychology professor has set a test for 50 students with each question passed scored as 1 and each question failed scored as 0 from a total of 100 questions.One week later the professor then asked the students to write down all the things they had passed that they could remember.These were scored as correctly remembered or incorrectly remembered by coders who were blind to the experimental conditions.He then conducts a within-samples t-test to compare the number passed with the number remembered and provides the SPSS output below. Which of the following statements is false?

Which of the following statements is true?

"Involving the relationship between two variables".What is this a glossary definition of?

A clinical psychologist has conducted a test of a new therapeutic treatment for anxiety disorders in which the new therapy is compared against a no-treament control condition.Colleagues point out that more of the participants are dropping out of the control condition to seek treatment elsewhere.To see whether this is the case, the researcher collects a new sample of 200 people experiencing anxiety disorders.She then randomly assigns them to either a no-treatment control (Cond.1)or a treatment (Cond.2)condition and records whether participants stayed with the program (Gp 1)or left early (Gp 2).The results of a chi-square test are shown below (with output taken from Preacher's, 2001, on-line tool). Which of the following statements is true?

"The largest probability that the researcher is prepared to accept in order to reject the null hypothesis.The probability of a random process producing a result as big as the one obtained has to be smaller than this for a statistical test to be significant.It is equal to the probability of making a Type I error and should be set before research is carried out." What is this a glossary definition of?

When researchers display reflexivity what does this involve?

"The hypothetical distribution of the expected ratio of variability between group means divided by variability within group means." What distribution is this a glossary definition of?

Which of the following does not compromise the results of t-tests?

A psychology professor has set a test for 50 students with each question passed scored as 1 and each question failed scored as 0 from a total of 100 questions.The professor conducted a one sample t-test shown in the SPSS output below. What are the values being compared in the test?

A personality researcher revisits the hypothesis that frustration leads to regression.She collects data from 49 female Internet users measuring their sense of personal frustration and their self-ratings of aggression.A scatterplot is shown below. Which of the following statements is true?

Which of the following statements is true?

After careful ethical review of planned procedures, a researcher tests a new brain activation drug by taking a sample of 50 volunteers and randomly assigning 25 participants to the treatment condition and 25 to the control (placebo)condition.She then carries out an fMRI scan to assess the level of activation in regions of the participants' brains 30 minutes after administering the drug.She carries out a between-participants t-test in SPSS which provides the output shown below: What further advice is appropriate to give the researcher here?

A developmental psychologist developed a training program to encourage children to reduce their Internet usage.To examine its efficacy he recruited a sample of 120 children - of whom 60 were aged 11 years and 60 were aged 13.Half of the participants were randomly assigned to the training program and the amount of online usage was measured after one month.Findings were subjected to two-way ANOVA, from which the output was as follows: Which of the following statements is true?