Placebo control groups and double-blind procedures are typically used to control for:
demand characteristics and experimenter effects
Which of the following is the best way to determine whether the differences in means obtained in an experiment are reliable?
replicate the experiment
The three steps of data analysis are:
check the data, summarize the data, and confirm what the data reveal.
After checking the data for errors and outliers, the next step in analyzing the data from a research study is to use:
A researcher observes that the main difference between two conditions is 2.0 and the average variability in participants' scores is 4.0. The effect size, Cohen's d, for this experiment is:
Which of the following is a meausre of the strength of the relationship between the independent and dependent variables that is independent of sample size?
Which of the following is not an advantage of using measures of effect size?
Measures of effect size provide the best info about whether the effect of the independent variable is statistically significant.
The statistical tool that is used to analyze the results of several independent experiments is called:
Two statistical methods that researchers use to determine whether an independent variable has a reliable effect on a dependent variable are:
null hypothesis testing and confidence intervals
The nonsystematic variation due to differences among subjects within each group is called:
A statistically significant outcome is an outcome that:
leads us to reject the null hypothesis
A statistically significant outcome is an outcome that:
has a small likelihood of occurring if the null hypothesis is true
A researcher computes an inferential statistic to test the difference between mean scores for an experimental group and a control group. The probability of the obtained statistical value is .025, which is less that the alpha level of significance (p<.05). The researcher should:
reject the null hypothesis of no difference between the experimental and control groups because the probability is so small; thus, the independent variable had a reliable effect on the dependent variable
We can be confident that the population means differ for two conditions of an experiment when the confidence intervals for the two sample means:
do not overlap
A researcher computes a 95% confidence interval for an experimental group to be 2.0 to 8.0 and computes a 95% confidence interval for a control group to be 0.0 to 4.0. Based on these confidence intervals, the researcher can state that:
the results for the effect of the independent variable on the dependent variable are inconclusive.
Our ability to draw appropriate conclusions based on the results of an experiment depends most of all on the:
internal validity of the experiment
The problem of type 1 and type 2 errors occurs bc:
decision making based on inferential statistics depends on probabilities
A type 1 error occurs when the null hypothesis is really true and we claim:
the independent variable did have an effect on behavior.
____________ refers to the researcher's ability to make causal inferences regarding an experiment outcome and _____________ refers to the resercher's ability to generalize the findings beyond the scope of the specific experiment.
Internal validity; external validity
When the results on an experiment are likely to be replicated if the procedures are repeated, we are more confident that the findings are not a result of chance factors. When this occurs, we state that our findings are:
In a clinical trial involving a double-blind placebo control design, a diet drug was shown to result in a statistically significant amount of weight loss. The sample size in this study was very large. The effect size reported for the drug was small (d=10). Which of the following best describes the outcome of this clinical trial?
The drug had reliable effect that will likely lead to a small weight loss for ppl who use it.
When the findings of experiments testing the effectiveness and safety of drugs on animals are confirmed in clinical trials with ppl, the original findings of the animal research are shown to have:
When the external validity of a finding can be established within appropriate ethical boundaries and when external validity is high priority for the research, the results of an experiment can be generalized on any dimension on which:
a representative sample has been included for that dimension
A researcher has read a research report indicating that a certain medication has been found to be effective when tested on men. The researcher plans to do an experiment testing the effectiveness of the same medication but in his experiment both men and women will be tested. The researcher is planning to do a :
partial replication of the experiment to test the external validity of the finding of the original experiment
Researchers found a relationship between insults and aggressive behavior for 5-year-olds. If they want to test the external validity of the conceptual relationship between insults and aggresive behavior for a sample of 35-year-olds, they should:
use age-appropriate insults and measures of aggression for the 35-year-olds
A cognitive psychologist wants to do an experiment testing the memory of elderly ppl. The psychologist has only 12 people available as possible participants; the independent variable she is manipulating requires the use of seperate groups for each condition; and she has a reliable and valid pretest she plans to use. Which design is this psychologist likely to use?
matched groups design
When conducting an experiment using the matched groups design, the preferred pretedt task (matching task) would be:
the same task that will be used as the dependent variable.
Which of the following conditions would lead you to recommend against the use of a matched groups design and in favor of a random groups design?
a large number of participants from a homogeneous population is available
To differentiate experiments involving individual differences (subject) variables and those involving manipulated independent variable, those experiments involving individual differences (subject) variable are called:
natural groups design
The natural groups design represents an illustration of the general research approach that is called:
Which of the following is the most critical problem in drawing causal inferences based on the natural groups design?
eliminating plausible alternative causes for the obtained relationship
The three image conditions represent the :
The scores on the questionnaire about body satisfaction represent the"
The alternative explanation that participants in the very thin image condition had lower body satisfaction than other participants before they viewed the experimental images is ruled out because the researcher:
randomly assigned participants to conditions
The alternative explanation that extraneous variables produced the different body satisfaction scores is ruled out bc the researcher:
asked all participants to view 10 images for 1 minute each
Assume that the average variability of participants' body satisfaction scores is 1.0. Based on this, we can state that the effect of viewing very thin images compared to athletic images is:
The use of very thin images and neutral images in this study represents:
a partial replication of previous findings for the effects of viewing body images
Which of the following is not one of the reasons why researchers choose to use the repeated measures design?
Repeated measured designs are generally lass sensitive than are independent groups designs
The difference between repeated measurements to establish test-retest reliability and experiments using repeated measure design is that in experiments with repeated measures designs:
measurements are compared for different conditions of an independent variable
There can be no confounding by individual differences variables in the repeated measures designs bc:
The same participants are tested in all conditions of repeated measures designs
Which of the following concerns leads researchers to balance practice effects in repeated measures designs?
balancing allows researchers to control changes participants undergo with repeated testing in repeated measures designs.
Counterbalancing is an important research technique bc it is used to:
average practice effects across conditions of a repeated measures design
The need to balance practice effects in the repeated measures design is analogous to the need to balance ________ in the independent groups design.
Balancing the order of conditions in a repeated measures design:
averages practice effects across the conditions of the experiment
A market wants to test the effectiveness of three diff. types of advertisement. Participants will respond to many example of each type of advertisement so that the researcher can determine each person's preference. What type if design is this researcher using:
complete repeated measures design
A researcher plan to conduct a complete repeated measures design in which the independent variable is manipulated using four conditions that vary the level of violence depicted in a photograph (none, low, medium, high). There are 10 photographs in each of the four conditions; thus, each participant will rate each photo once and therefore make a total of 40 ratings. If the researcher wishes to have 80 ratings for each photo, how many participants should should the researcher recruit?
A researcher designs an ex. with 6 conditions, but each condition takes only a short amount of time to administer. The researcher has the opportunity, therefore, to administer many trials of each condition in the experiment. Which of the following techniques is likely to be most effective for balancing practice effects?
A student is considering doing a complete repeated measures design ex. involving motor skills. The student's advisor has told him that ppl show a large initial improvement on the task followed by slow steady improvement after this initial change. The student must choose a technique for balancing practice effects. Which technique should the student not use?
When a participant in an ex. that involves the complete repeated measures design develops expectation ab which condition should occur next in the sequence, the methodological problem that occurs is called:
In the incomplete repeated measures design, the levels of the independent variable for each participant are perfectly confounded with the:
order in which the levels were presented
Practice effects in the incomplete repeated measures design are balanced by:
averaging across the results for all participants
Each of the 3 techniques that are used to balance practice effects in the incomplete repeated measures design conforms to a general rule that can be stated as:
each condition must appear in each ordinal position equally often.
A health psy. conducts an ex. to test the effectiveness of 4 techni. for helping a person to relax. The psy. has a limited # of ppl available to participate in the ex. and each relaxation techni. takes some time to complete. The psy. has decided, therefore, to use the incomplete repeated measures design with all poss. orders to balance practice effects, how many participants will the psy. need at a minimum?
When selected orders of conditions are used to balance practice effects in the incomplete repeated measures design:
the number of selected orders will always be equal to some multiple of the number of conditions in the experiment
Compared to random starting order with rotation, an advantage of the latin square tech. for selecting orders in the incomplete repeated measures design is that in the latin squre:
each condition precedes and follows each other condition exactly once
The additional step needed when analyzing the results in a complete repeated design is to:
compute the mean score for each participant for each condition of the experiment
Repeated measures designs are more sensitive than random grouops designs bc the systematic variation caused by individual differences is ________ the statistical analysis.
The problem of ________ occurs when the effects of the manipulation for a condition persist or carryover into the subsequent conditions in a repeated measures design
A repeated measures design ex. was done to test ppl's ability to solve problems that vaired in difficulty at 3 levels (easy, moderate, hard). The researcher used all poss. orders to balance pratice efects and so was able to determine that performance on the hard problems was better when they were preceded by a moderate difficulty problem than when they were preceded by an easy problem. Which of the following is a possible explanation of this finding?
The best solution when differential transfer is likely in an experiment is to:
conduct an independent groups design