Test 3 Flashcards by Courtney Baker

In a __________, the subjects in each group are different; that is, different people serve in control and experimental groups. (Different subjects are assigned to each group.)

between-subjects design

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By _______ _______ participants to conditions, we are trying to make the two groups as equivalent as possible.

randomly assigning

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A study is researching the effects of a study strategy on memory. One group uses the device while studying and another group does not use the device while studying. Each person in both groups is then given a memory test to determine any differences. Assuming everything was held constant (controlled), any difference observed would have to be due to the independent variable. If the study strategy group performed better, we could conclude that the study strategy caused memory to improve.
This memory study is known as a ___________.

posttest-only control group design

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An experimental design in which the dependent variable is measured after the manipulation of the independent variable.

posttest-only control group design

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An experimental design in which the dependent variable is measured both before and after manipulation of the independent variable.

pretest/posttest control group design

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The ___________ has the added advantage of ensuring that the subjects are equivalent at the beginning of the study.

pretest/posttest control group design

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The pretest/posttest control group design is not considered necessary if :

the subjects are randomly assigned and if the researcher uses a sufficiently large sample of subjects.

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There are disadvantages of pretest/posttest control group design, including the possibility of:

increasing demand characteristics and experimenter effects. (subject could guess what researchers are studying before posttest, and there is more opportunity for an experimenter to influence the subjects)

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A design with four groups that is a combination of the posttest only control group design and the pretest/posttest control group design, which minimizes the disadvantages and maximized the advantages.

Solomon four-group design.

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A ______ is an uncontrolled extraneous variable or flaw in an experiment.

confound

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If a study is confounded, then it is impossible to say:

whether changes in the dependent variable were caused by the independent variable or by the uncontrolled extraneous variable.

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Maximizing control of _________ can be very difficult.

human subjects

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The extent to which the results of an experiment can be attributed to the manipulation of the independent variable rather than to some confounding variable.

internal validity

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The process of determining whether a hypothesis is supported by the results of the research project is referred to as ______.

hypothesis testing

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It is impossible, statistically to demonstrate that something is true.
True or False

True

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Why do researchers create a null hypothesis?

Because statistical techniques are better at determining that something is not true, the researcher creates a null hypothesis to disprove, thus proving their initial hypothesis to be true.

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The hypothesis predicting that no difference exists between groups being compared is called the _____________.

null hypothesis

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Ho (capital H, little zero)

null hypothesis

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Whatever the research topic, the ___ predicts the opposite of that.

null hypothesis

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Create a null hypothesis (worded and in statistical notation) for the following statement:
Children who attend academic after-school programs have different IQ scores than those who do not.

Ho = Children who attend academic after-school programs have the same intelligence level as children that do not.
Ho: µo = µ1
or
Ho : µacademic program = µgeneral pop.

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Statistics allow us to _______ a hypothesis.

disprove or falsify

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If the null hypothesis is not supported, then the original hypothesis is ______.

supported or true

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The hypothesis that the researcher wants to support, predicting that a significant difference exists between groups being compared is called the ______.

alternative hypothesis (Ha) or the research hypothesis (H1)

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Create the statistical notation for the following research hypothesis:

Children who attend academic after-school programs have different IQ scores than those who do not.

Ha: µ1 ≠ µ2;
or
Ha: µacademic program ≠ µgeneral pop.

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An alternative hypothesis in which the researcher predicts that the groups being compared differ but does not predict the direction of the difference.

two-tailed hypothesis

Ha: µ1 ≠ µ2 | is a ________ hypothesis.

two-tailed (or non-directional) hypothesis, because it does not predict the direction of the difference. For example, it does not say Ha: µ1 > µ2

When using a two-tailed hypothesis, the researcher expects to find differences between the groups but is unsure what the differences will be. True or False

True

An alternative hypothesis in which the researcher predicts the direction of the expected difference between the groups is known as a __________.

one-tailed hypothesis

Ha : µo > µ1 is a _________ hypothesis

one-tailed hypothesis, because it is directional

Write the null hypothesis for the following: | Ha : µo > µ1

Ho : µo ≤ µ1

What are two types of hypothesis that can describe the following? Ho : µo ≤ µ1

null hypothesis (Ho), and one-tailed (directional, ≤)

Ho: µ academic program ≤ µ general pop. If the data collected found that the mean intelligence level of the children in academic after-school programs is "significantly" higher than the mean intelligence level for the population, then we would ________ the null hypothesis and ________ the alternative hypothesis.

reject the null, support the alternative

Ho: µ academic program ≤ µ general pop. If the mean IQ scores of the children in academic after-school programs are not significantly different from the population mean score, then the researcher has _______ the null hypothesis and ________ the alternative hypothesis.

failed to reject the null hypothesis and failed to support the alternative hypothesis.

Elimination is the best way of control: controls the highest number of threats to internal validity. a. true b. False

b. false

Random assignment is the following type of control: ________. a. constancy b. elimination c. statistical d. systematization

a. constancy

___ is used when both variables are string and the IV is between-subjects. a. Chi-square b. Independent t c. McNemar test d. Paired-t e. Pearson r

a. Chi-square

Bob’s HA is m1

b. reject HO

It is correct to say “retain the null hypothesis.” a. True b. false

a. True

The most effective way to control for ways that groups of participants can differ is ___. a. intact groups b. match-random assignment c. random assignment d. repeated measures

d. repeated measures

Rejecting the null hypothesis when it is true is a __. a. Correct decision b. Type I error c. Type II error

b. Type I error

In a study in which the number of helping behaviors is recorded for participants in two groups and the t-statistic is calculated, variability within the groups is the ____. a. denominator b. numerator c. quotient

a. denominator

If p (significance) = .06, you should say ___. a. fail to reject HA b. fail to reject HO c. reject HA d. reject HO

b. fail to reject HO

The appropriate inferential statistic for a yoked-control design with two levels and a numeric dependent variable is ____. a. Chi-square b. Independent t c. Paired t d. Pearson r

c. Paired t

Matching- random assignment can create a to external validity. a. true b. false

a. true

A repeated measures design controls sequence effects. a. true b. false

b. false

With a Before-Match-After design the participants are paired on a secondary variable. a. true b. false

b. false

You see a printout containing the following information: t(70) = 1.670, p = .04. You should decide ___. a. there is a significant difference in your 70 means b. there is not a significant difference in your two means c. there is a significant difference in your two means d. there is not a significant difference in your 70 means

c. there is a significant difference in your two means

You and a friend both ran an experiment with 20 participants in each level of the independent variable. You have 38 degrees of freedom and your friend has 19. Based on this information, which of the following is true? a. You had independent groups, your friend had dependent groups b. You had dependent groups, your friend had independent groups c. A decision cannot be made

a. You had independent groups, your friend had dependent groups

As Cohen’s D increases the overlap between groups __. a. decreases b. increases c. indeterminate

a. decreases

A researcher conducted a study to test the effect of Drug X on the number of racquetball games won five minutes after a participant consumed Drug X. Drug X is mixed in a container of water. Water is poured from the container into an eight-ounce glass. A participant then drinks four eight-ounce glasses. The best design for her study is ___. a. before-match-after b. match-by-correlated-criterion c. randomized two-group posttest only D.yoked-control

D.yoked-control

Assume there is no effect of the independent variable. Using our “intuitive explanation” of the t-test, the value of the t-statistic should be ___. a. large b. small c. indeterminate

b. small

The decision about the hypothesis should be the same whether a researcher uses "sig" or tcritical. a. true b. false

a. true

The researcher wants to reject the null hypothesis about homogeneity of variance when conducting an independent samples test. a. true b. false

b. false

An error in hypothesis testing in which the null hypothesis rejected when it is true.

Type I error

An error in hypothesis testing in which there is a failure to reject the null hypothesis when it is false.

Type II error

Anytime we make a decision using statistics, four outcomes represent correct decisions, where two represent errors. What are they?

reject Ho, Fail to reject Ho, | type I error and type II error.

If we reject the null hypothesis, but it turns out that we were incorrect and the results were due to chance it is a _______.

type I error

When we say there is no difference between groups (we fail to reject the null hypothesis) but in reality, there is a difference, we made a ________.

type II error

If we reject the Ho but the Ho is actually true, it is a _________.

Type I error

If we fail to reject Ho, but the Ho is actually false, it is a _____.

Type II error

An observed difference between two descriptive statistics (such as means) that is unlikely to have occurred by chance. (The difference between the groups is so large that we conclude it is due to something other than chance.)

statistical significance

To say that a result has statistical significance at the .05 level means that a difference as large as or larger than what we observed between the sample and the population could have occured by chance only ______.

5 times or less out of 100

In the social and behavioral sciences, alpha is typically set at ______ (as apposed to .01, .08 or anything else). This means that researchers in these areas are willing to accept up to a ___% risk of making a Type I error.

.05, 5%

If a person wants to reduce their risk of making a Type I error by lowering the alpha level to .01 (reducing risk to 1 out of 100 times), what will happen?

They will increase their chances of making a type II error. (If i reduce my risk of making a false alarm- saying a difference is there when it really is not, I increase my risk of missing a difference that really is there. When we reduce the alpha level, we are insisting on more stringent conditions for accepting our research hypothesis, making it more likely that we could miss a significant difference when it is present.

What type of error, Type I or Type II, do you think is considered more serious by researchers?

Most researchers consider a Type I error more serious. They would rather miss a result (Type II error) than conclude that there is a meaningful difference when there really is not (Type I error).

Determine the type of errors in the following examples: - A judge says a person is guilty when he is actually innocent. - A judge says a person is innocent when he is actually guilty. - A doctor says a patient does not have cancer when he actually does. - A doctor says a patient does have cancer when he actually does not.

- A judge says a person is guilty when he is actually innocent. TYPE I ERROR - A judge says a person is innocent when he is actually guilty. TYPE II ERROR - A doctor says a patient does not have cancer when he actually does. TYPE II ERROR - A doctor says a patient does have cancer when he actually does not. TYPE I ERROR

When the probability of a Type I error is low (.05 or less) is has ______.

statistical significance

A researcher hypothesizes that children in the South weigh less (because they spend more time outside) than the national average. Identify the Ho and Ha. Is it a one or two-tailed test?

Ho: µ southern children ≥ µ children in general Ha: µ southern children

A researcher collects data on children's weights from a random sample of children in the South and concludes that children in the South weigh less than the national average. The researcher, however, does not realize that the sample includes many children who are small for their age and that in reality there is no difference in weight between children in the South and the national average. What type of error is the researcher making?

Type I error

If a researcher decides to use the .10 level rather than the conventional .05 level of significance, what type of error is more likely to be made? Why? If the .01 level is used, what type of error is more likely? Why?

With the .10 level of significance, the researcher is willing to accept a higher probability that they result may be due to chance. Therefore, a Type I error is more likely to be made than if the researcher used the more traditional .05 level of significance. With a .01 level of significance, the researcher is willing to accept only a .01 probability that the result may be due to chance. In this case, a true result is more likely to be missed, meaning that a Type II error is more likely.

____ is the study of likelihood and uncertainty.

probability

The study of likelihood and uncertainty is to ______, as the process or determining whether a hypothesis is supported by the results of a research project is to _______.

probability, hypothesis testing

Inferential statistics allows us to infer something about the _______ based on the _______.

population; sample

The hypothesis predicting that differences exist between the groups being compared is the ______ hypothesis.

alternative

Null hypothesis is to alternative hypothesis as ______ is to _______. a. effect; no effect b. Type I error; Type II error c. no effect; effect d. none of the alternatives is correct

c. no effect; effect

A one-tailed hypothesis is to directional hypothesis as ________ hypothesis is to ______ hypothesis. a. null; alternative b. alternative; null c. two-tailed; nondirectional d. two-tailed; one-tailed

c. two-tailed; nondirectional

When using a one-tailed hypothesis, the researcher predicts ________.

the direction of the expected difference between the groups.

In a study of the effects of caffeine on driving performance, researchers predict that those in the group that is given more caffeine will exhibit worse driving performance. The researchers are using a ______ hypothesis.

both directional and one-tailed

In a recent study, researchers concluded that caffeine significantly increased anxiety levels. What the researchers were unaware of, however, was that several of the participants in the no-caffeine group were also taking anti-anxiety medications. The researchers' conclusion is an ________.

Type I error

When alpha is .05, that means that: a. the probability of a Type II error is .95 b. the probability of a Type II error is .05 c. the probability of a Type I error is .95 d. the probability of a Type I error is .05

d. the probability of a Type I error is .05

Test 3 Flashcards

(80 cards)