Questions and Answers of Statistics for Management

Is there enough statistical evidence to infer that there are differences between the three race categories (RACE) with respect to how likely they are to lose their jobs (JOBLOSE: 1 = Very likely, 2 =
Is there enough statistical evidence to conclude that Democrats, Republicans, and Independents (PARTYID3: 1 = Democrat, 2 = Independent, 3 = Republican) differ in their views about the federal income
Can we infer from the data that liberals, moderates, and conservatives (POLVIEWS3: 1 = Liberal, 2 = Moderate, 3 = Conservative) differ in their views about the federal income tax that they have to
Are there differences between the races with respect to their perceptions of their health (HEALTH: Would you say your own health, in general, is . . . 1. Excellent, 2. Good, 3. Fair, 4. Poor)? Use an
How does educational attainment affect newspaper readership? Is there enough evidence to conclude that there are differences between the five educational attainment groups (DEGREE: Highest degree
Test the following hypotheses:H0: s = 0H1: s ≠ 0n = 50 rs = .23 α = .05
Is there sufficient evidence at the 5% significance level to infer that there is a positive relationship between two ordinal variables given that rs = .15 and n = 12?
A statistics student asked seven first-year economics students to report their grades in the required mathematics and economics courses. The results (where 1 = F, 2 = D, 3 = C, 4 = B, 5 = A) are as
Does the number of commercials shown during a half-hour television program affect how viewers rate the show? In a preliminary study eight people were asked to watch a pilot for a situation comedy and
The weekly returns of two stocks for a 13-week period were recorded and are listed here. Assuming that the returns are not normally distributed, can we infer at the 5% significance level that the
The general manager of an engineering firm wants to know whether a draftsman€™s experience influences the quality of his work. She selects 24 draftsmen at random and records their years of
If the required condition is not satisfied conduct another more appropriate test to determine whether odometer reading and price are related.
At the completion of most courses in universities and colleges, a course evaluation is undertaken. Some professors believe that the way in which students fill out the evaluations is based on how well
Many people suffer from heartburn. It appears, however, that the problem may increase with age. A researcher for a pharmaceutical company wanted to determine whether age and the incidence and extent
Assume that the conditions for the test conducted in Exercise 16.6 are not met. Do the data allow us to conclude that the longer the commercial, the higher the memory test score will be?
Assume that the normality requirement in Exercise 16.7 is not met. Test to determine whether the price of a condominium and floor number are positively related.
Many people who quit smoking gain weight. Many explain that after they quit smoking food tastes better. To examine the relationship between smoking and taste, a researcher randomly sampled 280
Gambling on sports is big business in the United States and Canada. A television executive wants to know whether the amount of money wagered on a professional football game affects the enjoyment of
Do older Americans have a greater fear of losing their jobs? Test to determine whether there is enough evidence to conclude that as one gets older (AGE) the probability of losing one’s job (
Do the most satisfying jobs also produce the highest income? Test to determine whether there is enough evidence to infer that more satisfying jobs (SATJOB: 1 = Very satisfied, 2 = Moderately
Is there sufficient evidence to infer that more educated (EDUC) people read newspapers more often (NEWS: 1 = Every day, 2 = A few times per week, 3 = Once a week, 4 = Less than once a week, 5 =
What is meant by chance variation?
What is meant by special variation?
Your education as a statistics practitioner can be considered a production process overseen by the course instructor. The variable we measure is the grade achieved by each student.a. Discuss chance
If the control limits of an x chart are set at 2.5 standard errors from the centerline, what is the probability that on any sample the control chart will indicate that the process is out of control
Refer to Exercise 21.5. What is the average run length until the x chart signals that the process is out of control when it is under control?In exercise 21.5If the control limits of an x chart are
The control limits of an x chart are set at two standard errors from the centerline. Calculate the probability that on any sample the control chart will indicate that the process is out of control
Refer to Exercise 21.7. Determine the ARL until the x chart signals that the process is out of control when it is under control.In exercise 21.7The control limits of an x chart are set at two
On average, how many units will be produced until the control chart signals that the process is out of control when it is under control?A production facility produces 100 units per hour and uses an x
Refer to Exercise 21.9.a. Find the probability that the x chart does not detect a shift of 1.5 standard deviations on the first sample after the shift occurs.b. Compute the probability that the x
Refer to Exercise 21.12.a. Find the probability that the x chart does not detect a shift of 1.5 standard deviations on the first sample after the shift occurs.b. Compute the probability that the x
Refer to Exercise 21.13. What is the average run length to detect the shift?A production facility produces 100 units per hour and uses an x chart to monitor its quality. The control limits are set at
Write a brief report comparing the sampling plans described in Exercises 21.9 and 21.12. Discuss the relative costs of the two plans and the frequency of Type I and Type II errors.A production
Refer to Exercise 21.16.a. Find the probability that the x chart does not detect a shift of .75 standard deviation on the first sample after the shift occurs.b. Compute the probability that the x
Refer to Exercise 21.17. Find the average run length to detect the shift.A firm that manufactures notebook computers uses statistical process control to monitor all its production processes. For one
The company is considering changing the sampling plan so that 20 components are sampled every hour. What is the average number of units produced until the chart indicates that the process is out of
Refer to Exercise 21.19.a. Find the probability that the x chart does not detect a shift of .75 standard deviation on the first sample after the shift occurs.b. Compute the probability that the x
Refer to Exercise 21.20. What is the average run length to detect the shift?A firm that manufactures notebook computers uses statistical process control to monitor all its production processes. For
Write a brief report comparing the sampling plans described in Exercises 21.16 and 21.19. Discuss the relative costs of the two plans and the frequency of Type I and Type II errors.A production
Given the following statistics drawn from 30 samples of size 4, calculate the centerline and control limits for the x chart.x̅ = 453.6 S = 12.5
The mean of the sample means and the pooled standard deviation of 40 samples of size 9 taken from a production process under control are shown here. Compute the centerline, control limits, and zone
Refer to Exercise 16.46. Use a prediction interval with 90% confidence to predict the auction selling price of one Canada 1925 nickel with a grade of 40.Data from 16.46Refer to Exercise 3.70 where we
Refer to Exercise 16.45. Estimate with 95% confidence the mean time spent watching or reading news on the Internet for the population of people who have completed 12 years of education.In exercise
Will the prediction interval always be wider than the estimation interval for the same value of the independent variable? Briefly explain.
Briefly describe the difference between predicting a value of y and estimating the expected value of y.
Repeat Exercise 16.74 for amount spent on food away from home (FOODAWAY).In exercise 16.74How much more do households have to spend on food when there are children living at home?a. Conduct a test to
How much more do households have to spend on food when there are children living at home?a. Conduct a test to determine whether there is evidence of a positive linear relationship between total
It takes many years to build up capital gains. Use a statistical analysis to determine whether there is enough evidence to conclude that as one grows older one increases unrealized capital gains
Another way to interpret the results of Exercise 16.71 is that older people spend less on all food because their families are smaller (children have left home) or that they eat less expensive meals.
Are younger middle-class people more likely to eat out at restaurants than older people? Conduct a test to determine whether there is sufficient evidence to infer that age (AGE) and amount spent on
It seems obvious that for people who take out student loans more years of education lead to larger student debt.a. Conduct a test to determine whether there is a positive linear relationship between
An increasing number of people are attending colleges and universities. The effect of this trend is that younger people will be more educated than older people. Conduct a test to determine whether
Do you need more years of education to get further into debt? This question can be answered by determining the relationship between number of years of education (EDUC) and household debt (DEBT).
How does education (EDUC) affect financial success among the heads of middle class households? Conduct a regression analysis and determine the following.a. Is there evidence of a positive linear
We who educate would like to believe that people who have more education are more likely to do well professionally and financially. Fortunately, we have a number of surveys with real data to confirm
Refer to Exercise 3.71 wherein we looked at the relationship between temperature and distance that golf balls travel.a. Conduct a regression analysis to determine whether there is enough evidence of
National news on television features commercials describing pharmaceutical drugs that treat ailments that plague older people. Apparently, the major networks believe that older people tend to watch
Refer to Exercise 3.70 where we looked at the relationship between the grade of a particular coin (Canadian 1925 nickel) and its auction selling price.a. Is there sufficient evidence to conclude that
Assuming that the required conditions are satisfied in Exercise 16.13, what does this tell you about the distribution of used boat prices?Use a 5% significance level for all tests of hypotheses.
What are the required conditions for Exercise 16.8? Do these seem reasonable?
Describe what the required conditions mean in Exercise 16.6. If the conditions are satisfied, what can you say about the distribution of memory test scores?
Immigration has become a hot-button issue in American politics. One question that arises is: Are immigrants’ educational attainments different from those born in the United States? Conduct a test
A critical issue for service companies is how many customers cancel. Some wireless carriers lose an average of 3% of their subscribers each month. Should companies spend more effort getting new
A Gallup survey asked a random sample of federal government and private sector workers to judge their well-being. The responses are 1 = thriving, 2 = struggling, 3 = suffering. Is there enough
Refer to Exercise 15.45. Random samples from Denmark, Ireland, the Netherlands, and Sweden were drawn. Is the sufficient evidence to infer that there are differences in household types between the
To determine the actual side effects, pharmaceutical companies often conduct studies that compare the side effects of their drug versus the side effects of a placebo. One such study examined the side
The operations manager of a company that manufactures shirts wants to determine whether there are differences in the quality of workmanship among the three daily shifts. She randomly selects 600
Can we infer that the Survey of Consumer Finances in 2013 overrepresented at least one education category (EDCL)? Developing an Understanding of Statistical Concepts.
Can we infer that the General Social Survey in 2014 over represented at least one category of marital status (MARITAL)?
Using the data supplied by NOAA National Weather Service, 19,450 tornadoes struck the United States between 2000 and 2014. The percentage for each month is listed
From January 1 to December 31, 2011, there were 5,086 bank robberies in the United States. The percentage of that total for each day of the week is listed next. The number of robberies per day for
An aging pitcher has recorded the following pitch distribution over his long career from 1995 to 2014.1. Fast ball..................... 52%2. Curve ball.................. 19%3.
Refer to Exercise 15.15. After an entire season of pitches the following proportions for all pitches were observed.1. Pitch in the strike zone..................................................
Pitch trackers allow baseball fans watching televised games to see whether an umpire made the correct call. After tracking all pitches over an entire season the following probabilities were
Review the results of Exercises 15.1–15.3. What is the effect of decreasing the sample size?
Americans work longer hours than residents of most other countries. Does this mean that American-born workers work more than do immigrants?a. Conduct a statistical test to determine whether
Who watches more television (TVHOURS), Democrats or Republicans (PARTYID3: 1 = Democrat; 3 = Republican)? Conduct a test to determine whether Democrats beat Republicans in this category.
Do Americans become more Conservative as they grow older? If this is true we would expect that Conservatives would be older than Liberals (POLVIEWS3: 1 = Liberal, 3 =Conservative).a. Test to
Estimate with 95% confidence the change in the percentage of Americans who were working for themselves (WRKSLF: 1 = Selfemployed)) between 2012 and 2014.
The perception among many voters is that public servants don’t work very hard.a. Is there enough evidence to draw the conclusion that public sector employees (WRKGOVT: 1 = Government, 2 = Private)
If government workers (WRKGOVT: 1 = Government, 2 = Private) have more education it follows that they begin their careers later than do private sector employees. Does this mean that government
One of the advantages of working for someone else is that the number of hours of work per week is limited as opposed to the number of hours for self-employed people.a. Is there sufficient evidence to
Another way of measuring an aging society is to compute the number of children per family. Is there enough evidence to infer that the number of children per family has decreased in the decade
Innovation may be the key to creating high-value jobs. And innovation depends on education. Is there sufficient evidence to infer that the United States in 2014 is more educated than it was in 2004?
Are workers in 2014 working less than they did in 2004 (HRS1)? Test to determine whether there is enough evidence to answer the question affirmatively.
Is there sufficient evidence to infer that self-employed heads of households (OCCAT1: 1 = someone else, 2 = self-employed/partnership) have less net worth than heads of household who work for someone
Which political party is more educated? Conduct a test to determine whether differences in education (EDUC) actually exist among some of the eight political categories.
According to the Bureau of Labor Statistics, the average American family spent $2625 on food at restaurants. Is there enough evidence that wealthy households spend more than twice that figure
Refer to Exercise 13.5.a. Confirm that in each case the number of degrees of freedom for the equal-variances test statistic and confidence interval estimator is larger than that for the
A human resources manager for a car company wanted to know whether production-line workers have more days absent than office workers. He took a random sample of eight workers from each category and
The owner of a small book-publishing company is concerned about the declining number of people who read books. To learn more about the problem she takes a random sample of customers in a retail book
The operations manager of a manufacturer of television remote controls wants to determine which batteries last the longest in his product. He took a random sample of his remote controls and tested
An avid golfer has just purchased a new putter with a money-back guarantee. She plays seven rounds with the new putter and seven rounds with her old putter and records the number of putts. Can the
In a Reason-Rupe poll, a random sample of people were asked, “Just a rough guess, what percent profit on each dollar of sales do you think the average company makes after taxes?” The results from
Is there a tax on the poor? The tax on income is progressive in that higher income individuals pay at a high rate than lower-income people. For example, the top 0.1 percent of taxpayers earn 9.1
Study after study indicate that men earn higher incomes than women (SEX: 1 = Male, 2 = Female).a. To determine the extent of the differential in 2014 estimate the difference between male and female
Immigration has become an important topic in American politics. Some immigrants came o the United States to do jobs that Americans do not want to do. Many of these immigrants have little formal
Because many immigrants come to the United States with little money they often are willing to take risks that can result in high incomes. However, is this enough to overcome language and culture
In most countries including the United States, younger people tend to be on the left side of the political spectrum. If so, we would expect Republicans to be older than Democrats.a. Conduct a test to
Republicans tend to prefer smaller less intrusive government and lower taxes. Is this because Republicans have higher incomes (PARTYID3: 1 = Democrat; 3 = Republican)?a. Do the data allow us to

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