# frequency distribution

4. The following frequency distribution table lists the time (in minutes) that participants were late for an experimental session. Compute the sample mean, median, and mode for these data.

mean Correct: Your answer is correct. min

median Correct: Your answer is correct. min

mode 0 Incorrect: Your answer is incorrect. min

Time (min) Frequency

0 3

5 2

6 5

7 1

9 2

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7. A neuroscientist measures the reaction times (in seconds) during an experimental session in a sample of cocaine-addicted

(n = 8),

morphine-addicted

(n = 6),

and heroin-addicted rats

(n = 12).

Mean reaction times in each sample were 16, 14, and 12 seconds, respectively. What is the weighted mean for all three samples? Hint: The overall mean is not 14.0 seconds. (Round your answer to two decimal places.)

____________ sec

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9. A group of researchers measure the weight of five participants prior to a clinical weight loss intervention. They record the following weights (in pounds): 160, 110, 210, 310, and 260 pounds. The mean is 210 pounds.

Using the original example of five weights, the researchers added a sixth participant to the sample.

(a) If the sixth participant weighed 220 pounds, will the mean increase, decrease, or not change?

The mean will increase.

The mean will decrease.

The mean will not change.

(b) If the sixth participant weighed 210 pounds, will the mean increase, decrease, or not change?

The mean will increase.

The mean will decrease.

The mean will not change.

(c) If the sixth participant weighted 180 pounds, will the mean increase, decrease, or not change?

The mean will increase.

The mean will decrease.

The mean will not change.

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10. Gilman and colleagues (2008) measured general life satisfaction in 1,338 adolescents from two individualistic nations (Ireland, United States) and two collectivist nations (China, South Korea) using the Multidimensional Students’ Life Satisfaction Scale (MSLSS). Mean participant scores on the MSLSS are given in the following table.

Nation Gender Men Women

United States 4.39 4.61

Ireland 4.37 4.64

China 4.41 4.56

South Korea 3.92 3.78

(a) Among which group was general life satisfaction lowest on average?

women from South Korea

men from the United States

women from Ireland

men from South Korea

women from the United States

men from China men from Ireland

women from China

(b) Among which group was general life satisfaction highest on average?

women from South Korea

men from Ireland

men from South Korea

men from the United States

women from China

women from Ireland

women from the United States

men from China

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11. What are the degrees of freedom for sample variance?

n − 2

n + 1

n − 1

n

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12. Based on the empirical rule, what percentage of data fall within 1 SD, 2 SD, and 3 SD of the mean for data that are distributed normally? (Enter your answers to one decimal place.)

% of all scores lie within 1 SD of the mean

% of all scores lie within 2 SD of the mean

% of all scores lie within 3 SD of the mean

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13. A social scientist measures the number of minutes (per day) that a small hypothetical population of college students spends online.

Student Score Student Score

A 64 F 84