GAME SIGN IN INFORMATION: Go to http://www.mhpractice.com/ Login info:nline.edu Password LegsBoe24 Key Assignment Draft Module 3: Forecasting and Contracts In this module, players choose which contrac

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	1 min
median	2 min
mode	3 min

Time (min)	Frequency
0	2
2	5
4	2
7	1
9	3

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): 200, 250, 300, 100, and 150 pounds. The mean is 200 pounds.
Using the original example of five weights, the researchers added a sixth participant to the sample.

(a) If the sixth participant weighed 240 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 200 pounds, will the mean increase, decrease, or not change?

The mean will increase. The mean will decrease. The mean will not change.

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 Ireland women from the United States women from China men from South Korea men from the United States men from China women from South Korea men from Ireland

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

men from the United States men from Ireland women from South Korea women from Ireland women from China men from China men from South Korea women from the United States

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.)

1 % of all scores lie within 1 SD of the mean

2 % of all scores lie within 2 SD of the mean

3 % of all scores lie within 3 SD of the mean

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	73	F	89
B	94	G	98
C	39	H	82
D	98	I	89
E	53	J	99

(a) What is the range of data in this population?
1 min
(b) What is the IQR of data in this population?
2 min
(c) What is the SIQR of data in this population?
3 min
(d) What is the population variance?
4
(e) What is the population standard deviation? (Round your answer to two decimal places.)
5 min

14).A sociologist records the annual household income (in thousands of dollars) among a sample of families living in a high-crime neighborhood. Locate the lower, median, and upper quartiles for the times listed below. Hint: First arrange the data in numerical order.

lower quartile		1 thousand dollars
median		2 thousand dollars
upper quartile		3 thousand dollars

35	38
41	47
23	38
55	46
31	22

15) A psychopathologist records the number of criminal offenses among teenage drug users in a nationwide sample of 1,601 participants. To measure the variance of criminal offenses, he computes SS = 25,600 for this sample.

(a) What are the degrees of freedom for variance?
1
(b) Compute the variance and standard deviation.

variance	2
standard deviation	3

16). State whether each of the following will increase, decrease, or have no effect on the population variance.

(a) the sum of squares (SS) increases

This change will increase the population variance. This change will decrease the population variance. This change will have no effect on the population variance.

(b) the sample size decreases

This change will increase the population variance. This change will decrease the population variance. This change will have no effect on the population variance.

17). A researcher measures the time (in seconds) it takes a sample of five participants to complete a memory task. It took four of the participants 5, 6, 6, and 7 seconds. If

M = 6,

then what must be the fifth time recorded?
1 sec

18). An expert reviews a sample of 10 scientific articles

(n = 10)

and records the following number of errors in each article: 8, 6, 3, 5, 8, 2, 1, 5, 9, and 4. Compute SS, variance, and standard deviation for this sample using the definitional and computational formula. (Round your answers to two decimal places.)

SS		1
variance		2
standard deviation		3 errors

19). A professor records the time (in minutes) that it takes 16 students to complete an exam. Compute the SS, the variance, and the standard deviation assuming the 16 students constitute a population and assuming the 16 students constitute a sample. (Round your answers for variance and standard deviation to two decimal places.)

45	46	41	20
43	23	52	50
35	38	31	35
40	42	25	22

(a) the 16 students constitute a population

SS		1
variance		2
standard deviation		3 min

(b) the 16 students constitute a sample

SS		4
variance		5

20). To study bonding between mothers and infants, a researcher places each mother and her infant in a playroom and has the mother leave for 10 minutes. The researcher records crying time in the sample of infants during this time that the mother was not present and finds that crying time is normally distributed with

M = 6

and

SD = 1.2.

Based on the empirical rule, state the range of crying times within 68% of infants cried, 95% of infants cried, and 99.7% of infants cried.

(a) 68% of infants cried
1 to 2 min
(b) 95% of infants cried
3 to 4 min
(c) 99.7% of infants cried
5 to 6 min