Subject: Education / General Education
Question
We sample 20 new cars (sedans) and find the average miles per gallon (mpg) to be 26 with a standard deviation of 1.7.
1) If we increase our sample size to 40, what is the standard error of the mean?
In a sample of 100 BSC students, we find that on average students eat at a fast-food restaurant four times a week with a standard deviation of .5.
2) What is the standard error of the mean?
3) If our sample size is 1000, what is the standard error?
In a sample of 212 BSC students, we find that 82% are binge drinkers.
4) If we increase the sample size to 500, what is the standard error of the proportion?
Thirty out of 167 students have been involved in a violent conflict in in the past year.
5) If 90 students reported a violent conflict, what is the standard error of the proportions?
We sample 20 news cars (sedans) and find the average mpg to be 26 with a standard deviation of 1.7.
6) What is the 95% confidence interval (CI)
In a sample of 100 BSC students, we find that on average students eat at a fast-food restaurant four times a week with a standard deviation of .5.
7) What is the 95% CI?
8) What is the 99% CI?
In a sample of 212 BSC students, we find that 82% are binge-drinkers
9) What is the 99% CI?
EXERCISE 2
Use the cross-tabulation below to answer questions 1-3.
Homeowner or Renter of Respondent Cross-tabulation
WHITE
BLACK
OTHER
TOTAL
Homeowner or renter Owns home
Pays rent
Other
590
241
23
45
57
4
27
24
3
662
322
28
Total
852
106
54
1012
1) How many respondents own a home?
2) Of Whites, what percent own a home?
3) Which of the three groups is most likely to pay rent?
Use the table below to answer questions 4 & 5
Rap Music (3) Respondent’s Sex Cross-tabulation
MALE
FEMALE
TOTAL
Rap Music (3) Like it
Mixed feelings
Dislike it
Count
% Within
Respondent’s sex
Count
% Within respondent’s sex
Count
% Within respondent’s sex
56
15.3%
60
16.4%
250
68.3%
55
11.1%
109
22.0%
332
66.9%
111
12.9%
169
19.6%
582
67.5%
Total
Count
% Within respondents sex
366
100.0%
496
100.0%
862
100.0%
4) Of females, what percent like a rap music?
5) Are males or females more likely to like rap music?
Suppose that we want to know if males are more likely than females to live off campus. Use the data below to construct a cross-tabulation table. Be sure to include frequencies, column percent’s, and marginal values.
SEX
RESIDENCE
SEX
RESIDENCE
Male
Female
Female
Female
Male
Female
Female
Male
Female
Female
Female
Male
On-Campus
On-Campus
On-Campus
On-Campus
On-Campus
On-Campus
On-Campus
On-Campus
On-Campus
On-Campus
On-Campus
On-Campus
Female
Female
Female
Female
Male
Female
Female
Female
Male
Female
Female
On Campus
On Campus
On Campus
On Campus
On Campus
On Campus
On Campus
On Campus
On Campus
On Campus
On Campus
6) What percent of respondents are male?
7) Of females, what percent live off-campus?
8) Of those who live off-campus, what percent are female?
9) Use the table below to calculate chi-square:
Voting in 1992 election
Frequency
Percent
Valid Percent
Cumulative percent
Valid Voted
Did not vote
Not eligible
Refused
659
211
20
5
73.2
23.4
2.2
.6
73.6
23.6
2.2
.6
73.6
97.2
99.4
100.0
Total
Missing DK
NA
895
3
2
99.4
.3
.2
100.00
Total
Total
5
900
.6
100.0
10) Use the table below to calculate chi square:
Classical music (3) Education cross-tabulation
Less Than High School
High School of higher
Total
Classical music (3) Like it
Mixed Feelings
Dislike it
Count
% Within education
Count
% Within education
Count
% Within education
35
30.4%
23
20.0%
57
49.6%
403
54.2%
196
26.3%
145
19.5%
438
51.0%
219
25.5%
202
23.5%
Total
Count
% Within education
115
100.0%
744
100.0%
859
100.0%
For each of the problems below:
A) Draw a scatterplot.
B) Calculate Pearson’s r
C) Calculate the y-intercept, slope, and draw a regression line on the scatterplot.
D)Answer the “prediction” problem
E) Calculate r2 and explain what it tells us about the relationship between the variables
F) Calculate the t-ratio for Pearson’s r and determine the level of significance
11) A researcher wants to learn more about the relationship between the number of miles traveled to work and earnings. She hypothesizes that wealthier employees live outside the city rather than in the city and decides to sample a group of workers from a bank located downtown. She obtains the following data.
EARNINGS IN $ (X)
MILES TRAVELED TO WORK (Y)
33,250
84,500
66,350
58,425
45,600
67,240
77,900
5
21
6
7
8
14
10
Prediction problem: How far from the city does an employee earning 50,000 live?
12) A researcher wants to investigate the relationship between social networks and virtual social networks. She predicts that large virtual networks will be associated with large “real” networks. She develops two networking indices to measure networking that range from 0 to 50. Use the data below to access her hypothesis.
VIRTUAL SOCIAL NETWORKING SCORE (X)
“REAL SOCIAL NETWORKING SCORE (Y)
25
32
16
10
48
22
15
25
34
41
20
10
23
19
37
25
41
25
26
18
Prediction problem: What is the “real” networking score for a respondent with a virtual networking score of 30?
Order Now