Quiz 7 Flashcards
(20 cards)
The results of a recent poll on the preference of shoppers regarding two products are shown below
A. 800. 560
B. 900. 612
The point estimate for the difference between the two population proportions in favor of this product is
a. 0.44
b. 0.02
c. 100
d. 52
0.02
An insurance company selected samples of clients under 18 years of age and over 18 and recorded the number of accidents they had in the previous year. The results are shown below.
n1 = 500 n2=600
Number of accidents = 180. Number of accidents = 150
The pooled proportion is
a. 0.305
b. 0.027
c. 0.450
d. 0.300
0.300
An insurance company selected samples of clients under 18 years of age and over 18 and recorded the number of accidents they had in the previous year. The results are shown below.
n1 = 500 n2=600
Number of accidents = 180. Number of accidents = 150
The test statistic is
a. 2.96
b. 1.96
c. 0.96
d. 3.96
3.96
Salary information regarding male and female employees of a large company is shown below
Sample Size 64. 36
Sample Mean Salary (in 1,000) 44 41
Population Variance 128. 72
The 95% confidence interval for the difference between the means of the two populations is
a. -2 to 2
b. 0 to 6.92
c. -1.96 to 1.96
d. -0.92 to 6.92
-0.92 to 6.92
The daily production rates for a sample of workers before and after a training program are shown below.
Worker Before. After
1 20. 22
2 25 23
3 27 27
4 23 20
5 22 25
6 20 19
7 17 18
The null hypothesis to be tested is Ho: ud = 0. The test statistic is
a. 1.96
b. -1.96
c. 1.645
d. 0
0
The daily production rates for a sample of workers before and after a training program are shown below.
Worker Before. After
1 20. 22
2 25 23
3 27 27
4 23 20
5 22 25
6 20 19
7 17 18
Based on the results of question 18, the
a. null hypothesis should not be rejected
b. None of these alternatives is correct
c. alternative hypothesis should be accepted
d. null hypothesis should be rejected
Null hypothesis should NOT be rejected
A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken. You are given the following information
X- Bar 82 88
o^2 112.5. 54
n. 45. 36
The test statistic for the difference between the two population means is
a. -0.65
b. -3
c. -1.5
d. -0.47
-3
A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken. You are given the following information
X- Bar 82 88
o^2 112.5. 54
n. 45. 36
The p-value for the difference between the two population means is
a. 0.4986
b. 0.9972
c. 0.0014
d. 0.0028
0.0028
The following information was obtained from independent random samples
Assume normally dsitributed populations with equal variances
Sample Mean 45. 42
Sample Variance. 85 90
Sample Size. 10. 12
The degrees of freedom for the t-distribution are
a. 22
b. 20
c. 19
d. 21
20
The following information was obtained from independent random samples
Assume normally dsitributed populations with equal variances
Sample Mean 45. 42
Sample Variance. 85 90
Sample Size. 10. 12
The 95% confidence interval for the difference between the two population means is
a. -4.86 to 10.86
b. -5 to 3
c. -5.372 to 11.372
d. -2.65 to 8.65
c. -5.372 to 11.372
The management of a department store is interested in estimating the difference between the mean credit purchases of customers using the stores credit card vs those customers using a national major credit card. You are given the following information
Sample Size 64. 49
Sample mean. $140. $125
Population standard deviation. $10 $8
At 95% confidence, the margin of error is
a. 15
b. 3.32
c. 1.694
d. 1.96
b. 3.32
The management of a department store is interested in estimating the difference between the mean credit purchases of customers using the stores credit card vs those customers using a national major credit card. You are given the following information
Sample Size 64. 49
Sample mean. $140. $125
Population standard deviation. $10 $8
A 95% confidence interval estimate for the difference between the avaerage purchases of the customers using thhe two different credit cards is
a. 49 to 64
b. 125 to 140
c. 11.68 to 18.32
d. 8 to 10
c. 11.68 to 18.32
In order to determine whether or not there is a significant difference between the houly wages of two companies, the following data have been accumlated
Sample Size 80. 60
Sample Mean $6.75. $6.25
Population Standard Deviation. $1.00. $0.95
The p-value is
a. 0.0013
b. 0.0084
c. 0.0042
d. 0.0026
d. 0.0026
In order to determine whether or not there is a significant difference between the houly wages of two companies, the following data have been accumlated
Sample Size 80. 60
Sample Mean $6.75. $6.25
Population Standard Deviation. $1.00. $0.95
The null hypothesis
a. should be revised
b. None of these alternatives is correct
c. should not be rejected
d. should be rejected
d. should be rejected
If two independent large samples are taken from two populations, the sample distribution of the difference between two samples means
a. can be approximated by a Poisson distribution
b. can be approcimated by a normal distribution
c. will be a mean of one
d. will have a variance of one
b. can be approximated by a normal distribution
If we are interested in testing whether the proportion of items in population 1 is larger than the proportion of items in population 2, the
a. null hypothesis should state P1-P2 < 0
b. Alternative hypothesis should state P1-P2 < 0
c. null hypothesis should state P1-P2 >(greater or equal) 0
d. Alternative hypothesis should state P1-P2 > 0
d. Alternative hypothesis should state P1-P2 > 0
Two major automobile manyfacturers have a produced compact cars with the same size engines. We are interested in determining whether or not there is a significant difference in the MPG (miles per gallon) of the two brands of automobiles. A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each auto mobile for a specified distance. The following data show the results of the test.
Driver. Manufacturer A. Manufacturer B
1 32. 28
2. 27. 22
3. 26 27
4. 26 24
5. 25. 24
6. 29 25
7. 31 28
8. 25. 27
The mean for the differences is
a. 2.0
b. 2.5
c. 0.50
d. 1.5
a. 2.0
Two major automobile manyfacturers have a produced compact cars with the same size engines. We are interested in determining whether or not there is a significant difference in the MPG (miles per gallon) of the two brands of automobiles. A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each auto mobile for a specified distance. The following data show the results of the test.
Driver. Manufacturer A. Manufacturer B
1 32. 28
2. 27. 22
3. 26 27
4. 26 24
5. 25. 24
6. 29 25
7. 31 28
8. 25. 27
The test statistic is
a. 1.96
b. 2.256
c. 2.096
d. 1.645
b. 2.256
Two major automobile manyfacturers have a produced compact cars with the same size engines. We are interested in determining whether or not there is a significant difference in the MPG (miles per gallon) of the two brands of automobiles. A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each auto mobile for a specified distance. The following data show the results of the test.
Driver. Manufacturer A. Manufacturer B
1 32. 28
2. 27. 22
3. 26 27
4. 26 24
5. 25. 24
6. 29 25
7. 31 28
8. 25. 27
At 90% confidence, the null hypothesis
a. None of these alternatives is correct
b. should be rejected
c. should be revised
d. should not be rejected
b. should be rejected
When each data value in one sample is matched with a corresponding data value in another sample, the samples are known as
a. corresponding samples
b. None of these alternatives is correct
c. independent samples
d. matched samples
d. matched samples
