Question 1

A researcher is conducting a study to test the hypothesis that viewing family photos (as compared with viewing photos of strangers) prompts more autobiographical memories. State the null and alternative hypotheses for this study.

Accepted Answer

The answer of A researcher is conducting a study to...

Question 2

The degree of freedom is the most commonly reported measure of central tendency.

Accepted Answer

The degree of freedom is not a measure of central tendency. It is a statistical concept related to the sample size and the number of variables in the analysis. Measures of central tendency include mean, median, and mode.

Question 3

A graph of the means for different conditions in a study where each mean is graphed as a point and the points are connected in a line to show differences between mean scores is a line graph.

Accepted Answer

This is a correct definition of a line graph.

Question 4

If the p value is more than alpha, the test is said to be significant.

Accepted Answer

If the p value is more than alpha, the test is said to be not significant or fail to reject the null hypothesis. In order for a test to be significant, the p value must be less than or equal to the alpha level.

Question 5

Two-tailed hypotheses are typically made only when a researcher has a logical reason to believe that one particular direction of the effect will occur.

Accepted Answer

Two-tailed hypotheses can be made even when there is not a logical reason to believe that one particular direction of the effect will occur. This is done to be more conservative and to allow for the possibility of both positive and negative effects.

Question 6

Suppose that in reality the null hypothesis is true for this effect. In this case, what type of decision has been made in the above statement (correct, Type I error, or Type II error)?

Accepted Answer

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Question 7

Discuss why it is important to summarize what a study's data contain before trying to analyze if the sample is representative and our hypothesis supported.

Accepted Answer

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Question 8

The distribution of sample means is used to determine how likely it is that any sample mean will occur for a population.

Accepted Answer

The distribution of sample means helps us determine the likelihood of sample means occurring for a certain population.

Question 9

In the distribution of scores, 3, 8, 5, 9, 20, 4, the score "20" is an outlier.

Accepted Answer

An outlier is an observation that lies an abnormal distance from other values in a random sample from a population. In this case, the score "20" is much higher than the other scores, making it an outlier.

Question 10

A Type II error is an error made in a significance test when the researcher fails to reject the null hypothesis when it is actually false.

Accepted Answer

This statement accurately describes a Type II error.

Question 11

The critical region is the most extreme portion of a distribution of statistical values for the null hypothesis determined by the alpha level.

Accepted Answer

The critical region is indeed the most extreme portion of a distribution of statistical values for the null hypothesis, determined by the chosen alpha level (usually 0.05). It represents the area where we reject the null hypothesis in favor of the alternative hypothesis.

Question 12

The basic measures of central tendency of a distribution are: the mean, the median, and the range.

Accepted Answer

The basic measures of central tendency are the mean, the median, and the mode. The range is a measure of variability, not central tendency.

Question 13

Explain why it is necessary to set an alpha level of an inferential test.

Accepted Answer

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Question 14

For the study above, suppose the test to compare the conditions resulted in a p value of .037. What decision should the researcher make in this case?

Accepted Answer

The answer of For the study above, suppose the test...

Question 15

What does the p value in an inferential test represent?

Accepted Answer

The answer of What does the p value in an...

Question 16

A Type II error is an error made in a significance test when the researcher rejects the null hypothesis when it is actually true.

Accepted Answer

A Type II error occurs when the researcher fails to reject the null hypothesis when it is actually false, not when they reject it when it is true. Rejecting the null hypothesis when it is true is considered a Type I error.

Question 17

Reaction-time distributions typically include scores that are clustered around an average score that represents the typical speed of response.

Accepted Answer

This is correct, reaction-time distributions often exhibit a central tendency around an average score.

Question 18

For correlational studies with a predictor and outcome, the outcome variable is typically plotted on the x-axis.

Accepted Answer

The predictor variable is typically plotted on the x-axis and the outcome variable is plotted on the y-axis.

Question 19

One way that researchers sometimes estimate the population mean from the sample mean is with a confidence interval.

Accepted Answer

This is true. Confidence intervals provide a range of values that the population mean is likely to fall within, based on the sample mean and sample size, with a certain level of confidence.

Question 20

Correlation indicates a typical score in the distribution of collected scores.

Accepted Answer

Correlation measures the relationship between two variables, not a typical score in a distribution.

Quiz 7: Summarizing and Interpreting Data: Using Statistics