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Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 145558: As part of a study of corporate employees, the Director of Human Resources for PNC, Inc. wants to compare the distance traveled to work by employees at their office in downtown Cincinnati with the distance for those in downtown Pittsburgh. A sample of 35 Cincinnati employees showed they travel a mean of 370 miles per month, with a standard deviation of 30 miles per month. A sample of 40 Pittsburgh employees showed they travel a mean of 380 miles per month, with a standard deviation of 26 miles per month. At the .05 significance level, is there a difference in the mean number of miles traveled per month between Cincinnati and Pittsburgh employees?
Click here to see answer by stanbon(26259)   |
Question 145632: 15.24 High levels of cockpit noise in an aircraft can damage the hearing of pilots who are exposed to this
hazard for many hours. A Boeing 727 co-pilot collected 61 noise observations using a handheld
sound meter. Noise level is defined as “Low” (under 88 decibels), “Medium” (88 to 91 decibels), or “High” (92 decibels or more). There are three flight phases (Climb, Cruise, Descent). Research
question: At α = .05, is the cockpit noise level independent of flight phase? (Data are from
Capt. Robert E. Hartl, retired.) Noise
Noise Level Climb Cruise Descent Row Total
Low 6 2 6 14
Medium 18 3 8 29
High 1 3 14 18
Col Total 25 8 28 61
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Question 145617: Three new colors have been proposed for the Jeep Grand Cherokee vehicle. They are silvered-blue, almond, and willow green. The null hypothesis for a goodness-of-fit test would be
A) willow green preferred over the other colors.
B) no preference between the colors.
C) any one color preferred over the other colors.
D) impossible to determine.
E) none of the above.
Click here to see answer by stanbon(26259) |
Question 145630: 15.18 Sixty-four students in an introductory college economics class were asked how many credits they
had earned in college, and how certain they were about their choice of major. Research question:
At α = .01, is the degree of certainty independent of credits earned? Certainty
Credits Earned Very Uncertain Somewhat Certain Very Certain Row Total
0–9 12 8 3 23
10–59 8 4 10 22
60 or more 1 7 11 19
Col Total 21 19 24 64
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Question 145629: 15.22 A student team examined parked cars in four different suburban shopping malls. One hundred vehicles
were examined in each location. Research question: At α = .05, does vehicle type vary by
mall location? (Data are from a project by MBA students Steve Bennett, Alicia Morais, Steve
Olson, and Greg Corda.) Vehicles
Vehicle Type Somerset Oakland Great Lakes Jamestown Row Total
Car 44 49 36 64 193
Minivan 21 15 18 13 67
Full-sized Van 2 3 3 2 10
SUV 19 27 26 12 84
Truck 14 6 17 9 46
Col Total 100 100 100 100 400
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Question 145719: 1. Nancy Giggles has not been doing well on statistics examinations. She decides to sample 12 of her friends to determine the number of hours spent studying for Test 3 and the score out of 100 received on that test. The results:
Test 4 Score Hours of study
47 7
55 10
87 39
98 43
37 2
71 12
100 51
98 48
85 23
82 26
56 7
78 14
(i) Find the equation of the regression line using the least square technique. Interpret the meanings conveyed by the regression equation.
(ii) Compute the correlation coefficient and the coefficient of Determination. Interpret these values.
2. David Gallano, a wine merchant, has selected opinions on grape wine quality from a random sample of his customers. The customers tasted wine made from grapes grown in three regions of the country. The customers rated wine quality on a scale of 1 (best) to 4 (worst). The sample data looks like:
Customer Quality Rating of Wine by Grape-growing region
Quality Rating
Growing Region
I Growing Region
II Growing Region
III Row Total
1 15 10 6 31
2 7 13 12 32
3 11 12 8 31
4 3 8 15 26
Column Total
36 43 41 120
David wants to know whether quality ratings are independent of the grape-growing region. Can you conclude at a 95% confidence that the quality rating is independent of the growing region?
Click here to see answer by stanbon(26259) |
Question 145671: For a chi-square test involving a contingency table, suppose the null hypothesis is rejected. We conclude that the two variables are
A) linear.
B) curvilinear.
C) not related.
D) related.
E) none of the above.
Click here to see answer by stanbon(26259) |
Question 145827: What are the assumptions for using ANOVA?
A) The sampled populations follow the normal distribution.
B) The populations have equal standard deviations.
C) The samples are randomly selected and are independent
D) None of the above
E) All of the above
Click here to see answer by stanbon(26259) |
Question 145826: Which of the following assumptions are required for nonparametric tests?
A) Each population is normally distributed
B) The populations have equal variances
C) The errors are both random and independent
D) All of the above
E) None of the above
Click here to see answer by stanbon(26259) |
Question 145821: The names of three potential presidential candidates, Smith, Jones and Green, were presented to a focus group to determine the preferences of voters. The null hypothesis would be:
A) There is no preference among the candidates
B) There are definite preferences among the candidates
C) Green is preferred over the other two
D) More degrees of freedom are required
E) This cannot be determined without more information
Click here to see answer by stanbon(26259) |
Question 145859: Please, help me with these questions, Thanks.
1. Nancy Giggles has not been doing well on statistics examinations. She decides to sample 12 of her friends to determine the number of hours spent studying for Test 3 and the score out of 100 received on that test. The results:
Test 4 Score
Hours of study
47
7
55
10
87
39
98
43
37
2
71
12
100
51
98
48
85
23
82
26
56
7
78
14
(i) Find the equation of the regression line using the least square technique. Interpret the meanings conveyed by the regression equation.
(ii) Compute the correlation coefficient and the coefficient of Determination. Interpret these values.
2. David Gallano, a wine merchant, has selected opinions on grape wine quality from a random sample of his customers. The customers tasted wine made from grapes grown in three regions of the country. The customers rated wine quality on a scale of 1 (best) to 4 (worst). The sample data looks like:
Customer Quality Rating of Wine by Grape-growing region
Quality Rating
Growing Region
I
Growing Region
II Growing Region
III
Row Total
1
15
10
6
31
2
7
13
12
32
3
11
12
8
31
4
3
8
15
26
Column Total
36
43
41
120
David wants to know whether quality ratings are independent of the grape-growing region. Can you conclude at a 95% confidence that the quality rating is independent of the growing region?
Click here to see answer by stanbon(26259) |
Question 145867: What are the assumptions for using ANOVA?
A) The sampled populations follow the normal distribution.
B) The populations have equal standard deviations.
C) The samples are randomly selected and are independent
D) None of the above
E) All of the above
Click here to see answer by stanbon(26259) |
Question 145946: I do not have an isbn number it is not a textbook, sorry!
A pair of dice is rolled, what are the odds of each of the following
A)A sum of seven
b) a sum of 11
c) a sum of 7 or a 11 turning up
d) a sum of 2 or a sum of 12 turning
e) a sum greater than 9 turning up is
Thankyou
Click here to see answer by stanbon(26259) |
Question 145924: 4. Which of the following statements is true?
a. As the standard deviation of the population increases, the standard error of the mean increases.
b. As the standard deviation of the population increases, the mean of the sampling distribution of means increases.
c. As the population mean increases, the mean of the sampling distribution of means decreases.
d. As the sample size increases, the standard error of the mean increases.
Click here to see answer by vleith(1977) |
Question 145932: Which of the following does NOT hold true for the t distribution?
A) Confidence intervals will be wider than for large samples.
B) The region of acceptance will be larger than for large samples.
C) A larger computed t value will be needed to reject the null hypothesis than for large samples using z.
D) There is only one t distribution.
E) None of the above.
Click here to see answer by stanbon(26259) |
Question 145926: 6. For any given level of a, a confidence interval that is constructed using the t distribution will utilize a t value corresponding to an area of _________ in the tails of the distribution.
a. 2a
b. a
c. a/2
d. a/4
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Question 146016:
Can’t cook 750
No time to cook 115
Can’t take food on the go 87
High cost 58
Poor taste 43
Hard to find 28
Confusion about nutrition 13
Use the above chart, which shows the results of a survey in which 1094 adults were asked why they don’t always eat healthy food. Find the probability of randomly selecting an adult from the sample who feels that healthy foods have high cost OR are hard to find. ___________________
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Question 146015: Saturday you wash and dry 9 pair of pants you have 4 blue jeans, 2 khakis and 3 black. You close your eyes and randomly pick a pair out of the dryer, what is the probability that you will first select and remove a black pair, AND then you select a pair of blue jeans? ________________
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Question 146014: The table shows the results of a survey in which 142 men and 145 women workers ages 25 to 64 were asked if they have at least one month’s income set aside for emergencies.
Men Women Total
Less than one month’s income 66 83 149
One month’s income or more 76 62 138
Total 142 145 287
Find the probability that a randomly selected worker has one month’s income or more set aside for emergencies. ____________
Given that a randomly selected worker is male, find the probability that the worker has less than one month’s income. ____________
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Question 145930: What does the appropriate use of the t distribution for hypothesis testing assume about the population?
A) Near normal in shape
B) Standard deviation is known
C) Positively skewed
D) Standard deviation is unknown
E) Both “a” and “d” are correct
Click here to see answer by nabla(412) |
Question 146066: Do a larger proportion of college students than young children eat cereal? Researchers surveyed both age groups to find the answer. The results are shown in the table below. (a) State the hypotheses used to answer the question. (b) Using α = .05, state the decision rule and sketch it. (c) Find the sample proportions and z statistic. (d) Make a decision. (e) Find the p-value and interpret it. (f) Is the normality assumption fulfilled? Explain
Statistic College Students (ages 18–25) Young Children (ages 6–11)
Number who eat cereal x1 = 833 x2 = 692
Number surveyed n1 = 850 n2 = 740
Click here to see answer by stanbon(26259) |
Question 146065: Has the cost to outsource a standard employee background check changed from 2005 to 2006? A random sample of 10 companies in spring 2005 showed a sample average of $105 with a sample standard deviation equal to $32. A random sample of 10 different companies in spring 2006 resulted in a sample average of $75 with a sample standard deviation equal to $45. (a) Conduct a hypothesis test to test the difference in sample means with a level of significance equal to .05. Assume the population variances are not equal. (b) Discuss why a paired sample design might have made more sense in this case.
Click here to see answer by stanbon(26259) |
Question 146099: how would i do this? A box of 6 coins (penny, nickel, dime or quarter) worth $0.67 is shaken. What is the probability that a nickel is drawn first and then a quarter? Assume no replacement and that all coins are equally likely.
Click here to see answer by vleith(1977) |
Question 146098This question is from textbook 
: how would i do this? The letters of the word Mississippi are placed in a hat. What is the probability that the first two letters drawn are both i if the first letter drawn is not replaced?
This question is from textbook
Click here to see answer by checkley77(7035) |
Question 146112: Test at the 0.01 level the statement that 55% of those families who plan to purchase a vacation residence in Florida want a condominium. The null hypothesis is = 0.55 and the alternate is is not equal to 0.55. A random sample of 400 families who planned to buy a vacation residence revealed that 228 families want a condominium. What decision should be made regarding the null hypothesis?
Click here to see answer by stanbon(26259) |
Question 146159: A cognitive retraining clinic assists outpatient victims of head injury, anoxia, or other conditions
that result in cognitive impairment. Each incoming patient is evaluated to establish an appropriate
treatment program and estimated length of stay. To see if the evaluation teams are consistent,
12 randomly chosen patients are separately evaluated by two expert teams (A and B) as shown. At
the .10 level of significance, are the evaluator teams consistent in their estimates? State your
hypotheses and show all steps clearly.
Estimated Length of Stay in Weeks
Patient
Team 1 2 3 4 5 6 7 8 9 10 11 12
A 24 24 52 30 40 30 18 30 18 40 24 12
B 24 20 52 36 36 36 24 36 16 52 24 16
Click here to see answer by stanbon(26259) |
Question 146161: Please can someone Take a look at Problems 145964, 145965, 145966, 145967, 145968, 145969, and 145970-74? I posted these on friday and I really do need help with these as soon as conveniently possible. Thanks.
Click here to see answer by stanbon(26259) |
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