Question 1 of 23
0.0/ 1.0 Points
The chi-square goodness-of-fit test can be used to test for:
Incorrect A.difference between population variances
B.normality
C.significance of sample statistics
D.difference between population means
Answer Key: B
Question 2 of 23
0.0/ 1.0 Points
The data presented in the table below resulted from an experiment in which seeds of 5 different types were planted and the number of seeds that germinated within 5 weeks after planting was recorded for each seed type. At the .01 level of significance, is the proportion of seeds that germinate dependent on the seed type?
Seed Type
Observed Frequencies
Germinated
Failed to Germinate
1
31
7
2
57
33
3
87
60
4
52
44
5
10
19
A.Yes, because the test value 16.86 is greater than the critical value of 13.28
B.Yes, because the test value 16.86 is less than the critical value of 14.86
Incorrect C.No, because the test value 16.86 is greater than the critical value of 13.28
D.No, because the test value 13.28 is less than the critical value of 16.86
Answer Key: A
Part 2 of 16 - 3.0/ 3.0 Points
Question 3 of 23
1.0/ 1.0 Points
The marketing manager of a large supermarket chain would like to use shelf space to predict the sales of pet food. For a random sample of 12 similar stores, she gathered the following information regarding the shelf space, in feet, devoted to pet food and the weekly sales in hundreds of dollars. .
Store
1
2
3
4
5
6
Shelf Space
5
5
5
10
10
10
Weekly Sales
1.6
2.2
1.4
1.9
2.4
2.6
Store
7
8
9
10
11
12
Shelf Space
15
15
15
20
20
20
Weekly Sales
2.3
2.7
2.8
2.6
2.9
3.1
Compute the value of the sample correlation coefficient between weekly sales and shelf space.
Correct A.0.827
B.0.684
C.0.652
D.0.308
Answer Key: A
Question 4 of 23
1.0/ 1.0 Points
A single variable X can explain a large percentage of the variation in some other variable Y when the two variables are:
Correct A.highly correlated
B.mutually exclusive
C.inversely related
D.directly related
Answer Key: A
Question 5 of 23
1.0/ 1.0 Points
The city of Oakdale wishes to see if there is a linear relationship between the temperature and the amount of electricity used (in kilowatts). Based on the data in the table below, is there a significant linear relationship between temperature and the amount of electricity used? These data are also available in the worksheet temperature in the Excel workbook Temperature.xlsx.
Temperature.xlsx
Temperature (x)
73
78
85
98
93
81
76
105
Kilowatts (y)
680
760
910
1510
1170
837
600
1800
A.No, the sample correlation coefficient is equal to 0.098, which does not provide evidence of a significant linear relationship.
B.No, the sample correlation coefficient is equal to 0.981, which does not provide evidence of a significant linear relationship.
Correct C.Yes, the sample correlation coefficient is equal to 0.981, which provides evidence of a significant linear relationship.
D.Yes, the sample correlation coefficient is equal to 0.878, which provides evidence of a significant linear relationship.
Answer Key: C
Part 3 of 16 - 2.0/ 2.0 Points
Question 6 of 23
1.0/ 1.0 Points
Multiple myeloma or blood plasma cancer is characterized by increased blood vessel formulation in the bone marrow that is a prognostic factor in survival. One treatment approach used for multiple myeloma is stem cell transplantation with the patient’s own stem cells. The following data represent the bone marrow microvessel density for a sample of 7 patients who had a complete response to a stem cell transplant as measured by blood and urine tests. Two measurements were taken: the first immediately prior to the stem cell transplant, and the second at the time of the complete response.
Patient
1
2
3
4
5
6
7
Before
158
189
202
353
416
426
441
After
284
214
101
227
290
176
290
Perform an appropriate test of hypothesis to determine if there is evidence, at the .05 level of significance, to support the claim that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant? What is the value of the sample test statistic?
A.z = 1.8424
B.t = 2.7234
C.p = 2.7234
Correct D.t = 1.8424
Answer Key: D
Question 7 of 23
1.0/ 1.0 Points
Members of the general adult population volunteer an average of 4.2 hours per week. A random sample of 20 female college students and 18 male college students produced the results given in the table below. At the .01 level of significance, is there sufficient evidence to conclude that a difference exists between the mean number of volunteer hours per week for male and female college students?
Females
Males
Sample size
20
18
Sample mean
3.8
2.5
Sample variance
3.5
2.2
A.No, because the test value 2.38 is greater than the critical value
Correct B.No, because the test value 2.38 does not exceed the critical value
C.No, because the test value 2.90 is greater than the critical value
D.Yes, because the test value 2.90 is greater than the critical value
Answer Key: B
Part 4 of 16 - 3.0/ 3.0 Points
Question 8 of 23
1.0/ 1.0 Points
A two-tailed test is one where:
A.negative sample means lead to rejection of the null hypothesis
B.results in only one direction can lead to rejection of the null hypothesis
C.no results lead to the rejection of the null hypothesis
Correct D.results in either of two directions can lead to rejection of the null hypothesis
Answer Key: D
Question 9 of 23
1.0/ 1.0 Points
A null hypothesis can only be rejected at the 5% significance level if and only if:
A.the null hypothesis is biased
Correct B.a 95% confidence interval does not include the hypothesized value of the parameter
C.a 95% confidence interval includes the hypothesized value of the parameter
D.the null hypotheses includes sampling error
Answer Key: B
Question 10 of 23
1.0/ 1.0 Points
In an article appearing in Today’s Health a writer states that the average number of calories in a serving of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from 75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean number of calories per serving to be 78 with a sample standard deviation of 7.
At the a = .05 level of significance, does the nutritionist have enough evidence to reject the writer’s claim?
A.Yes
Correct B.No
C.Cannot Determine
Answer Key: B
Part 5 of 16 - 2.0/ 2.0 Points
Question 11 of 23
1.0/ 1.0 Points
Find the 95% confidence interval for the standard deviation of the lengths of pipes if a sample of 26 pipes has a standard deviation of 10 inches.
A.14.0 < \f$\sigma \f$ < 16.0
Correct B.7.8 < \f$\sigma \f$ < 13.8
C.74.0 < \f$\sigma \f$ < 126.0
D.60.8 < \f$\sigma \f$ < 190.5
Answer Key: B
Question 12 of 23
1.0/ 1.0 Points
A sample of 25 different payroll departments found that the employees worked an average of 310.3 days a year with a standard deviation of 23.8 days. What is the 90% confidence interval for the average days worked by employees in all payroll departments?
A.301.0 < \f$\mu \f$ < 319.6
B.298.0 < \f$\mu \f$ < 322.6
Correct C.302.2 < \f$\mu \f$ < 318.4
D.314.1 < \f$\mu \f$ < 316.8
Answer Key: C
Part 6 of 16 - 1.0/ 1.0 Points
Question 13 of 23
1.0/ 1.0 Points
The standard normal distribution has a mean of ___ and standard deviation of ___, respectively.
Correct A.0 and 1
B.1 and 0
C.1 and 1
D.0 and 0
Answer Key: A
Part 7 of 16 - 0.0/ 1.0 Points
Question 14 of 23
0.0/ 1.0 Points
The following data were obtained from a survey of college students. The variable X represents the number of non-assigned books read during the past six months.
x
0
1
2
3
4
5
P (X=x)
0.20
0.25
0.20
0.15
0.10
0.10
What is the standard deviation of X?
A.3.24
B.1.58
Incorrect C.1.24
D.2.0
Answer Key: B
Part 8 of 16 - 1.0/ 1.0 Points
Question 15 of 23
1.0/ 1.0 Points
What type of probability uses sample spaces to determine the numerical probability that an event will occur?
Correct A.classical probability
B.subjective probability
C.conditional probability
D.empirical probability
Answer Key: A
Part 9 of 16 - 1.0/ 3.0 Points
Question 16 of 23
1.0/ 3.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
Staples, a chain of large office supply stores, sells a line of desktop and laptop computers. Company executives want to know whether the demands for these two types of computers are dependent on one another. Each day's demand for each type of computers is categorized as Low, Medium-Low, Medium-High, or High. The data shown in the table below is based on 200 days of operation. Based on these data, can Staples conclude that demands for these two types of computers are independent? Test at the 5% level of significance.
desktops
low med-low med-high high
low 3 14 14 4 35
laptops med-low 6 18 17 22 63
med-high 13 16 11 16 56
high 8 14 15 9 46
30 62 57 51 200
What is the test value for this hypothesis test?
Answer: Correct15.31 Round your answer to two decimal places.
What is the critical value for this hypothesis test?
Answer: Correct233.99 Round your answer to two decimal places.
What is the conclusion for this hypothesis test? Choose one.
1. At the .05 level of significance, Staples can conclude that demands for these two types of computers are independent.
2. At the .05 level of significance, Staples can conclude that demands for these two types of computers are dependent.
Answer: Correct2 Enter only a 1 or 2 for your answer.
Answer Key: 15.31, 16.92, 1
Part 10 of 16 - 1.0/ 1.0 Points
Question 17 of 23
1.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
A company has observed that there is a linear relationship between indirect labor expense (ILE) , in dollars, and direct labor hours (DLH). Data for direct labor hours and indirect labor expense for 18 months are given in the file ILE_and_DLH.xlsx
Treating ILE as the response variable, use regression to fit a straight line to all 18 data points.
Using your estimated regression output, predict the indirect labor expenses for a month in which the company has 31 direct labor hours.
Place your answer, rounded to 1 decimal place, in the blank. Do not use any stray punctuation marks or a dollar sign. For example, 458.9 would be a legitimate entry. Correct525.4
Answer Key: 525.4
Part 11 of 16 - 0.0/ 1.0 Points
Question 18 of 23
0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
Two teams of workers assemble automobile engines at a manufacturing plant in Michigan. A random sample of 145 assemblies from team 1 shows 15 unacceptable assemblies. A similar random sample of 125 assemblies from team 2 shows 8 unacceptable assemblies.
If you are interested in determining if there is sufficient evidence to conclude, at the 10% significance level, that the two teams differ with respect to their proportions of unacceptable assemblies, what is/are the critical value you would use to conduct such a test of hypothesis?
Place your answer, rounded to 2 decimal places, in the blank. If there are two critical values, place only the positive value in the blank. For example, 2.34 would be a legitimate entry. Correct.2469
Answer Key: 1.64|1.65
Part 12 of 16 - 1.0/ 1.0 Points
Question 19 of 23
1.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
A popular retail store knows that the purchase amounts by its customers is a random variable that follows a normal distribution with a mean of $30 and a standard deviation of $9.
What are the two dollar amounts, equidistant from the mean of $30, such that 98% of all customer purchases are between these values? Place your answers in the blanks provided. Do not include a dollar sign. For example, 14.25 would be a legitimate entry.
Lower value Correct9.01
Upper value Correct50.99
Answer Key: 8.06|10.06, 49.94|51.94
Part 13 of 16 - 0.0/ 1.0 Points
Question 20 of 23
0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
A sample of 9 production managers with over 15 years of experience has an average salary of $71,000 and a sample standard deviation of $18,000.
Assuming that s = 18,000 is a reasonable estimate for \f$\sigma \f$ what sample size would be needed to ensure that we could estimate the true mean salary of all production managers with more than 15 years experience within $4200 if we wish to be 95% confident? Place your answer, as a whole number, in the blank. Do not use a dollar sign, a comma, or any other stray mark. For examples, 34 would be a legitimate entry. Correct43
Answer Key: 71
Part 14 of 16 - 1.0/ 1.0 Points
Question 21 of 23
1.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
Ann is applying for a bank loan to open a pizza franchise. She must first complete a written application and then, if the written application is approved, be interviewed by bank officers. If an applicant’s written application is not approved the applicant is not granted an interview with the bank officers. Past records for this bank show that the probability of an applicant having his or her written application approved is 0.63. Records also indicate that the interviewing committee of bank officers approves 85% of the individuals they interview. Find the probability that Ann’s loan request is approved. Place your answer, rounded to 2 decimal places, in the blank. For example, 0.76 would be a legitimate entry. Correct.54
Answer Key: 0.45|0.65
Part 15 of 16 - 0.0/ 1.0 Points
Question 22 of 23
0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
The ABC battery company claims that their batteries last at least 100 hours, on average. Your experience with their batteries has been somewhat different, so you decide to conduct a test to see if the company's claim is true. You believe that the mean life is actually less than the 100 hours the company claims. You decide to collect data on the average battery life (in hours) of a random sample of n = 20 batteries. Some of the information related to the hypothesis test is presented below.
Test of H0: \f$\mu \geq \f$ 100 versus H1: \f$\mu < \f$ 100
Sample mean 98.5
Std error of mean 0.777
Assuming the life length of batteries is normally distributed, what is the value of the test statistic used to conduct your test of hypothesis? Place your answer, rounded to 3 decimal places in the blank. For example, -2.345 would be a legitimate entry. Correct1.932
Answer Key: -1.932|-1.930
Part 16 of 16 - 0.0/ 1.0 Points
Question 23 of 23
0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
An ice cream vendor sells three flavors: chocolate, strawberry, and vanilla. Forty five percent of the sales are chocolate, while 30% are strawberry, with the rest vanilla flavored. Sales are by the cone or the cup. The percentages of cones sales for chocolate, strawberry, and vanilla, are 75%, 60%, and 40%, respectively. For a randomly selected sale, define the following events:
\f$A_{1}\f$ = chocolate chosen
\f$A_{2}\f$ = strawberry chosen
\f$A_{3}\f$ = vanilla chosen
\f$B\f$ = ice cream on a cone
\f$\bar{B}=\f$ ice cream in a cup
Find the probability that the ice cream was sold in a cup and was strawberry flavor. Place your answer, rounded to 2 decimal places, in the blank. For exampe, 0.34 would be a legitimate entry. Correct.1634
Answer Key: 0.12
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