Psych 212 exam one questions

one advantage of the correlated-groups t-test over the independent-groups t-test is that it reduces the error variance due to

better control of individual differences

dr. talskey randomly and evenly assigns 32 athletes to two different types of motivational training programs and then assesses the quality of goals they set for their personal life after the training and wants to see if the two groups differ from each other

between subjects design

when using a design employing random assignment, assuming the same data values, the standard error term for the independent groups t-test will typically be

bigger than the standard error of the mean difference calculated for correlated groups t-test

this concept is often problematic among studies that feed into the college sophomore problem, but conceptual and systematic replication may help address and strengthen the concept of

external validity

a limitation in the ability to differentiate between scores at the bottom of the scale is a _______ and a limitation in the ability to differentiate between scores at the top of the scale is a ______

floor effect; ceiling effect

a researcher makes the following conclusion in their APA results section: t (18) = 1.41, p > .05 which of the next possible steps should they not do?

calculate effect size

if the null hypothesis is true, then the t test should be close to

0.00

if subjects are used in multiple conditions exploring the effect of different stress levels on task performance, but doing so results in their getting better at the task each time due to practicing, then the results may be confounded by

carryover effects

Concerns for within-subjects designs frequently include _____ and _____.

carryover effects, order effects

an independent groups t-test

compares sample means for two unrelated groups or samples

when making estimations about a population via sampling, instead of hypothesis testing for significance, researchers could report margins of error by calculating and reporting

confidence intervals

a memory researcher is studying the potential positive effects of sleep on memory. he believes that students who get some sleep after memorization will recall information better. using a sample of 18 students, in one condition all subjects study information and then nap for 30 minutes before taking a test on the information they studied. in the other condition, the same students study information (formerly established as being equal in difficulty via pilot testing) and then watch television for 30 minutes before taking the same test on the information they studied. the conditions are counterbalanced to control for carryover and order effects

correlated groups t test

an industrial psychologist wants to see if workers score on a compassion measure is a predictor of how well they perform as customer service representatives. to test this relationship, she has 60 workers complete a 20 item compassion index and also obtains their overall performance rating (10 point scale) from their personnel files

correlational design

a mechanism for controlling order effects either by including all orders or treatment presentations or by randomly determining the order for each participants is

counterbalancing and/or a latin square

which of the following is not an assumption of the t-test for independent groups

heterogeneity of the variances indicating different variances between groups

researchers are conducting an exploratory study on a new drug's effects on blood pressure. the study is testing two groups of individuals randomly assigned to either using a competitors drug for one group of 13 subjects and the new drug for the other group of 12 subjects. they believe that the new drug will reduce blood pressure better than the competitor's drug

independent groups t test

After grading 20 very poor term papers, Professor Jones was so upset by his students' writing that he became even more conscious of errors in their papers. Professor Jones' change in his grading criteria is similar to the confound of

instrumentation

researchers are conducting a study on a new drug's effects on blood pressure. the study is testing two groups of individuals who first complete a health inventory. subjects are paired up based on their scores on this health inventory. one from each pair is then assigned to either the placebo group or the experimental drug group. both groups take their respective interventions and are monitored for the dependent variable, blood pressure

matched groups design

teresa believes that girls keep their rooms cleaner than boys. she finds 26 pairs of brothers and sisters (each pair belongs to the same family) and rates the cleanliness of their separate rooms. by ensuring that the study use siblings from the same family, socialization and parenting influences are controlled for

matched groups design

changes that occur naturally in the subjects, over time could result in the confound of

maturation

cohen's d and r^2 are both what type of statistics playing what role

measures of effect size to determine the strength of the findings

when subjects are lost at different rates from the experimental and control groups, any observed effect may be due to

mortality/attrition

creativity scores are collected from 30 students enrolled in an art program. researchers want to find out if students who are taking art classes have a higher degree of artistic ability compared to students who are not enrolled in an art program. the creativity test has a population mean of 45.62, but we are not given the population standard deviation

one sample t test

drawing from the beer and pricing study discussed in class, identify the two factors below that limited the external validity of the research study

only one type of beer was studied and only full time graduate students were subjects

single blind experiments help to control for ________ effects whereas double-blind experiments help to control for _________ effects

participant; experimenter and participant

if conducting a matched groups design to explore differences in marital satisfaction between those attending a marriage enrichment seminar and a control group, a researcher would do which of the following steps?

rank them on a variable you want to control like years married, pair them based on rankings, and then randomly assign to conditions

a researcher is interested in exploring the relationship (in either direction) between one's GPA and how much time they spend on social media. 12 subjects keep a daily log of their estimated time spent on social media over a week, and the overall average daily time spent is entered into a data base along with their 12 GPAs obtained from the registrar with the subjects permission

significance test of the correlation

a researcher finds a significant effect relative to their alpha level of .05; and therefore rejects the null hypothesis. The researcher:

still may have committed a type 1 error

drawing from the beer and pricing study discussed in class, identify the two factors below that were confounds, systematic threats to the internal validity of the study

the order in which subjects drank the beer and the letter labels that were applied to the beer cans

To say that an experiment contains a confound means that

there is an uncontrolled extraneous variable in the experiment

24 clients with severe depression were selected for a study and their daily adaptive behavior was measured for a week giving them a single pre-test total adaptiveness score. all of the clients received a month long mentoring experience with an individual who has successfully overcome depression having once been in that institution. after the month long experience, their daily adaptive behaviors were measured again over a week period providing a second (this time post-test) total adaptiveness score

within subjects design

iq test scores are collected from 30 students enrolled in private schools. researchers want to find out if students who go to private schools have a higher iq than those enrolled in public schools. the mean of the 30 randomly chosen private school students is compared against the population mean for all students enrolled in public schools within that district and the data base allows for a determination of the population standard deviation as well

z test