for Respect writer:
fox4
question.docx
1. In a sample of size of 10, the sum of all values is 400. What is the sample mean
a. 20 c. 800
b. 560 d. None of the above
SHOW YOUR WORK!
2. The following are the durations in minutes of a sample of long-distance phone calls within the continental United States reported by one long-distance carrier
Table 1
Time (in minutes) Relative Frequency
0 but less than 5 0.37
5 but less than 10 0.22
10 but less than 15 0.15
15 but less than 20 0.10
20 but less than 25 0.07
25 but less than 30 0.07
30 or more 0.02
Referring to Table 1, what is the width of each class?
a. 1 minute c. 5 minutes
b. 2% d. 100%
SHOW YOUR WORK!
3. Referring to Table 1, what is the cumulative relative frequency for the percentage of calls that lasted under 20 minutes?
a. 0.10 c. 0.59
b. 0.76 d. 0.84
SHOW YOUR WORK!
4. What is the difference between the standard deviation, standard error of the mean, and standard error of the estimate? Discuss
5. The managers of a brokerage firm are interested in finding out if the number of new clients a broker brings into the firm affects the sales generated by the broker. They sample 4 brokers and determine the number of new clients they have enrolled in the last year andtheir sales amounts in thousands of dollars. These data are presented in the table that follows.
Broker Clients (Y) Sales (X)
1 1 4
2 2 6
3 1 3
4 0 1
a. Construct a scatter diagram for these data. Does the scatter diagram show a linear relationship between sales and number of new clients? Explain and show all work!
Y
6
5
4
3
2
1
0 1 2 3 X
b) Estimate the intercept (b0). Show your work
c) Estimate the slope (b1). Show your work
c) Draw the regression line
6. Fitting a straight line to a set of data yields the following prediction line:
Y = 2 + 5X
i) Interpret the meaning of the Y intercept, b0.
ii) Interpret the meaning of the slope, b1
iii) Predict the mean value of Y for X = 3
7. If SSR = 66 and SST = 88, compute the coefficient of determination, r2, and interpret its meaning.
8. The Management at Ohio National Bank does not want its customers to wait in line for service for too long. The manager of a branch of this bank estimated that the customers currently have to wait an average of 8 minutes for service. Assume that the waiting times for all customers at this branch have a normal distribution with a mean of 8 minutes and a standard deviation of 2 minutes.
Find the probability that randomly selected customer will have to wait for less than 3 minutes?
: Show all steps:
1. Draw the normal curve and indicate the mean, standard deviation, and the X bar scale
2. Identify the area of interest (that is shade the area under the curve that you will compute the probability).
3. Covert the X bar values in Z scores
4. Look up the Z standardized table for the cumulative area(s).
5. Now, make your decision ( that a customer will wait for less than 3 minutes)
9. The Management at Ohio National Bank does not want its customers to wait in line for service for too long. The manager of a branch of this bank estimated that the customers currently have to wait an average of 8 minutes for service. Assume that the waiting times for all customers at this branch have a normal distribution with a mean of 8 minutes and a standard deviation of 2 minutes.
What is the probability that customers have to wait for 6 to 8 minutes?
: Show all steps:
1. Draw the normal curve and indicate the mean, standard deviation, and the X bar scale
2. Identify the area of interest (that is shade the area under the curve that you will compute the probability).
3. Covert the X bar values in Z scores
4. Look up the Z standardized table for the cumulative area(s).
5. Now, make your decision ( that a customer will have to wait for 6 to 8 minutes)
10. An entrepreneur is considering the purchase of a coin-operated laundry. The current owner claims that over the past 5 years, the average daily revenue was $675 with a standard deviation of $75. A sample of 30 days reveals daily revenue of $625.
Consider H0: µ = 675 versusHa: µ < 675
Use α = .01, would you reject the null hypothesis? Show all steps!
1. State the Hypothesis
2. Draw the normal distribution and identify the acceptance and rejection regions
3. Compute the Z STAT value
4. Compare your ZSTAT with the Z Tabled value.
5. Make you decision
11. Five hundred employees were selected from a city’s large private companies, and they were asked whether or not they have any retirement benefits provided by their companies. Based on this information, the following two-way contingency table was prepared.
Have Retirement Benefits
Yes No Total
Men 225 75
Women 150 50
Total
If one employee is selected at random from these 500 employees,
a) Find the probability that this employee is a woman
b) Has retirement benefits
c) Has retirement benefits given the employee is a man
d) Is a woman given that she does not have retirement benefits
12. Use the given data to construct a frequency distribution. Lori asked 24 students how many hours they had spent doing homework during the previous week. The results are shown below:
Number of students Hours of study
3. Covert the X bar values in Z scores
4. Look up the Z standardized table for the cumulative area(s).
5. Now, make your decision ( that a customer will have to wait for 6 to 8 minutes)
10. An entrepreneur is considering the purchase of a coin-operated laundry. The current owner claims that over the past 5 years, the average daily revenue was $675 with a standard deviation of $75. A sample of 30 days reveals daily revenue of $625.
Consider H0: µ = 675 versusHa: µ < 675
Use α = .01, would you reject the null hypothesis? Show all steps!
1. State the Hypothesis
2. Draw the normal distribution and identify the acceptance and rejection regions
3. Compute the Z STAT value
4. Compare your ZSTAT with the Z Tabled value.
5. Make you decision
11. Five hundred employees were selected from a city’s large private companies, and they were asked whether or not they have any retirement benefits provided by their companies. Based on this information, the following two-way contingency table was prepared.
Have Retirement Benefits
Yes No Total
Men 225 75
Women 150 50
Total
If one employee is selected at random from these 500 employees,
a) Find the probability that this employee is a woman
b) Has retirement benefits
c) Has retirement benefits given the employee is a man
d) Is a woman given that she does not have retirement benefits
12. Use the given data to construct a frequency distribution. Lori asked 24 students how many hours they had spent doing homework during the previous week. The results are shown below:
Number of students Hours of study
|
1 |
11 |
|
2 |
10 |
|
3 |
11 |
|
4 |
9 |
|
5 |
11 |
|
6 |
11 |
|
7 |
15 |
|
8 |
12 |
|
9 |
11 |
|
10 |
8 |
|
11 |
13 |
|
12 |
10 |
|
13 |
10 |
|
14 |
13 |
|
15 |
11 |
|
16 |
10 |
|
17 |
13 |
|
28 |
11 |
|
19 |
10 |
|
20 |
12 |
|
21 |
10 |
|
22 |
13 |
|
23 |
12 |
|
24 |
9 |
|
|
|
Construct a frequency distribution, using 4 classes and a class width of 2 hours, and a lower limit of 8 for class 1.
