Questions and Answers of Introductory Statistics Behavioral

The following table gives the 2015 total payroll (in millions of dollars) and the percentage of games won during the 2015 season by each of the American League baseball teams.Compute the linear
The following table gives the 2015 total payroll (in millions of dollars) and the percentage of games won during the 2015 season by each of the National League baseball teams.Compute the linear
For a sample data set on two variables, the value of the linear correlation coefficient is (close to) zero. Does this mean that these variables are not related? Explain.
For a sample data set, the slope b of the regression line has a negative value. Which of the following is true about the linear correlation coefficient r calculated for the same sample data?a. The
For a sample data set, the linear correlation coefficient r has a positive value. Which of the following is true about the slope b of the regression line estimated for the same sample data?a. The
Can the values of B and ρ calculated for the same population data have different signs? Explain.
What does a linear correlation coefficient tell about the relationship between two variables? Within what range can a correlation coefficient assume a value?
Explain the difference between A and a and between B and b for a regression model.
Explain why the random error term ε is added to the regression model.
Describe the mean, standard deviation, and shape of the sampling distribution of the slope b of the simple linear regression model.
The following table gives the 2015 total payroll (in millions of dollars) and the percentage of games won during the 2015 season by each of the National League baseball teams.a. Find the standard
What are the degrees of freedom for a simple linear regression model?
The following table gives the 2015 total payroll (in millions of dollars) and the percentage of games won during the 2015 season by each of the American League baseball teams.a. Find the least
The following table gives the 2015 total payroll (in millions of dollars) and the percentage of games won during the 2015 season by each of the National League baseball teams.a. Find the least
Two variables x and y have a negative linear relationship. Explain what happens to the value of y when x increases. Give one example of a negative relationship between two variables.
Two variables x and y have a positive linear relationship. Explain what happens to the value of y when x increases. Give one example of a positive relationship between two variables.
Explain the difference between y and ŷ.
Explain the least squares method and least squares regression line. Why are they called by these names?
Why is the random error term included in a regression model?
Explain the meaning of independent and dependent variables for a regression model.
The one-way ANOVA test is alwaysa. Right-tailed b. Left-tailed c. Two-tailed
In 2014, the variance of the ages of all workers at a large company that has more than 30,000 workers was 133. A recent random sample of 25 workers selected from this company showed that the variance
A sample of 10 units selected from a normally distributed population produced a variance of 7.2. Test at a 1% significance level if the population variance is greater than 4.2.
A sample of 21 units selected from a normally distributed population produced a variance of 9.2. Test at a 5% significance level if the population variance is different from 6.5.
According to a Gallup poll whose results were reported on October 22, 2013, American’s views on legalizing marijuana are changing. In that survey, American adults were asked whether marijuana
In a recent poll, American adults were asked, if they have a choice, would they prefer to live in a city, suburb, or countryside. The following table shows the frequencies for the three choices.Test
In a Harris Poll conducted October 15–20, 2014, American adults were asked “to think ahead 2 to 5 years and assess if they feel solar energy will contribute to meeting our energy needs.” Of the
In a Pew Research Center poll conducted December 3–8, 2013, American adults age 18 and older were asked if Christmas is more a religious or a cultural holiday for them. Of the respondents, 51% said
A random sample of 1000 Americans was taken, and these adults were asked if experience in politics was necessary for a candidate to be president of America. The following table presents the results
To make a test of independence or homogeneity, what should be the minimum expected frequency for each cell? What are the alternatives if this condition is not satisfied?
Find the critical value of F for an F distribution with .025 area in the right tail anda. df = (4, 11)b. df = (15, 3)
Find the critical value of F for an F distribution with df = (3, 12) anda. Area in the right tail = .05b. Area in the right tail = .10
Determine the critical value of F for the following.a. df = (6, 12) and area in the right tail = .01b. df = (6, 40) and area in the right tail = .01c. df = (6, 100) and area in the right tail = .01
Find the critical value of F for the following.a. df = (2, 6) and area in the right tail = .025b. df = (6, 6) and area in the right tail = .025c. df = (15, 6) and area in the right tail = .025
Find the critical value of F for the following.a. df = (3, 3) and area in the right tail = .05b. df = (3, 10) and area in the right tail = .05c. df = (3, 30) and area in the right tail = .05
In a Gallup poll conducted August 7–10, 2014, American adults aged 18 and older were asked, “If you were taking a new job and had your choice of a boss, would you prefer to work for a man or a
The chi-square goodness-of-fit test is alwaysa. Two-tailed b. Left-tailed c. Right-tailed
According to a Bureau of Labor Statistics report released on March 25, 2015, statisticians earn an average of $84,010 a year and accountants and auditors earn an average of $73,670 a year
According to a Bureau of Labor Statistics report released on March 25, 2015, statisticians earn an average of $84,010 a year and accountants and auditors earn an average of $73,670 a year (www.bls.
In a survey of American drivers, 79% of women drivers and 85% of men drivers said that they exceeded the speed limit at least once in the past week. Suppose that these percentages are based on random
When are the samples considered large enough for the sampling distribution of the difference between two sample proportions to be (approximately) normal?
A finger-tapping experiment was conducted by a doctoral neuropsychology student. The purpose of this experiment was to determine bilateral nervous system integrity, which provides data about the
To make a goodness-of-fit test, what should be the minimum expected frequency for each category? What are the alternatives if this condition is not satisfied?
Explain the difference between the observed and expected frequencies for a goodness-of-fit test.
What is a goodness-of-fit test and when is it applied? Explain.
To test the hypothesis that the mean blood pressure of university professors is lower than that of company executives, which of the following would you use?a. A left-tailed testb. A two-tailed
According to an estimate, 75% of cell phone owners in a large city had smart phones in 2014. In a recent sample of 1000 cell phone owners selected from this city, 790 had smart phones. At a 2%
PolicyInteractive of Eugene, Oregon conducted a study of American adults in April 2014 for the Center for a New American Dream. Seventy-five percent of the adults included in this study said that
According to a Bureau of Labor Statistics release of February 20, 2015, 79% of American children under age 18 lived with at least one other sibling in 2014. Suppose that in a recent sample of 2000
According to a Bureau of Labor Statistics release of March 25, 2015, financial analysts earned an average of $110,510 in 2014. Suppose that the 2014 earnings of all financial analysts had a mean of
The following information was obtained from two independent samples selected from two populations with unequal and unknown population standard deviations.n1 = 48 x̅1 =
The following information was obtained from two independent samples selected from two normally distributed populations with unequal and unknown population standard deviations.n1 = 14
The following information was obtained from two independent samples selected from two populations with unequal and unknown population standard deviations.n1 = 48 x̅1 =
The following information was obtained from two independent samples selected from two normally distributed populations with unequal and unknown population standard deviations.n1 = 14
The standard recommendation for automobile oil changes is once every 5000 miles. A local mechanic is interested in determining whether people who drive more expensive cars are more likely to follow
According to the Kaiser Family Foundation, U.S. workers who had employer-provided health insurance paid an average premium of $1170 for single (one person) health insurance coverage during 2013
A one-tailed testa. Has one rejection regionb. Has one non-rejection regionc. Both a and b
A two-tailed test is a test witha. Two rejection regionsb. Two non-rejection regionsc. Two test statistics
In a Gallup poll conducted July 7–10, 2014, 45% of Americans said that they actively try to include organic foods into their diets (www.gallup.com). In a recent sample of 2100 Americans, 1071 said
According to an article in Forbes magazine of April 3, 2014, 57% of students said that they did not attend the college of their first choice due to financial concerns (www.forbes.com). In a recent
According to a 2014 CIRP Your First College Year Survey, 88% of the first-year college students said that their college experience exposed them to diverse opinions, cultures, and values
According to the U.S. Census Bureau, in 2014, 62% of Americans age 18 and older were married. A recent sample of 2000 Americans age 18 and older showed that 58% of them are married. Can you reject
According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. Suppose that in a recent sample of 1500 shoppers, 315 stated that they
According to the analysis of Federal Reserve statistics and other government data, American households with credit card debts owed an average of $15,706 on their credit cards in August 2015
According to ValuePenguin, the average annual cost of automobile insurance was $1388 in the state of Nevada in 2014 (www. valuepenguin.com). An insurance broker is interested to find if the current
The XO Group Inc., released the results of its annual Real Weddings Study on March 27, 2014 (www.theknot.com). According to this study, the average cost of a wedding in America was $29,858 in 2013. A
According to a survey by the College Board, undergraduate students at private nonprofit four-year colleges spent an average of $1244 on books and supplies in 2014–2015 (www.collegeboard.org). A
According to Moebs Services Inc., the average cost of an individual checking account to major U.S. banks was $380 in 2013 (www.moebs.com). A bank consultant wants to determine whether the current
Powerball is a game of chance that has generated intense interest because of its large jackpots. To play this game, a player selects five different numbers from 1 through 69, and then picks a
Terry & Sons makes bearings for autos. The production system involves two independent processing machines so that each bearing passes through these two processes. The probability that the first
In a Gallup Annual Economy and Personal Finance poll, conducted April 3–6, 2014, 21% of adults aged 18 to 29 said that college costs and loans were the biggest financial problem their families were
According to the National Association of Colleges and Employers, the average starting salary of 2014 college graduates with a bachelor’s degree was $45,473 (www.naceweb.org). A random sample of
According to the U.S. Bureau of Labor Statistics, all workers in America who had a bachelor’s degree and were employed earned an average of $1224 a week in 2014. A recent sample of 400 American
For each of the following significance levels, what is the probability of making a Type I error?a. α = .025 b. α = .05 c. α = .01
Consider the following null and alternative hypotheses:H0: μ = 60 versus H1: μ > 60Suppose you perform this test at α = .01 and fail to reject the null hypothesis.Would you state that the
Consider the following null and alternative hypotheses:H0: μ = 25 versus H1: μ ≠ 25Suppose you perform this test at α = .05 and reject the null hypothesis.Would you state that the difference
By rejecting the null hypothesis in a test of hypothesis example, are you stating that the alternative hypothesis is true?
What does the level of significance represent in a test of hypothesis? Explain.
Consider H0: μ = 55 versus H1: μ ≠ 55.a. What type of error would you make if the null hypothesis is actually false and you fail to reject it?b. What type of error would you make if the null
Which of the two hypotheses (null and alternative) is initially assumed to be true in a test of hypothesis?
Harris Interactive conducted an online poll of 2097 Americanadults between July 17 and 21, 2014, on the topic “Who are we lying to?” In response to one of the questions, 37% of American adults
In an online poll conducted by the St. Louis Post-Dispatch during September 2014, people were asked about their favorite sports to watch on television. Of the respondents, 42% selected baseball, 18%
In a January 2014 survey conducted by the Associated Press- We TV, 68% of American adults said that owning a home is the most important thing or a very important but not the most important thing
According to a Gallup poll conducted April 3–6, 2014, 21% of Americans aged 18 to 29 said that college loans and/or expenses were the top financial problem facing their families. Suppose that this
According to a Gallup poll conducted January 5–8, 2014, 67% of American adults were dissatisfied with the way income and wealth are distributed in America. Assume that this poll is based on a
What is the point estimator of the population proportion, p?
What assumption(s) must hold true to use the normal distribution to make a confidence interval for the population proportion, p?
The following data give the one-way commuting times (in minutes) from home to work for a random sample of 30 workers.a. Calculate the value of the point estimate of the mean one-way commuting time
According to the 2015 Physician Compensation Report by Medscape (a subsidiary of WebMD), American orthopedists earned an average of $421,000 in 2014. Suppose that this mean is based on a random
How will you interpret a 99% confidence interval for μ? Explain.
What is the margin of error of estimate for μ when σ is known? How is it calculated?
Briefly explain the difference between a confidence level and a confidence interval.
What is the point estimator of the population mean, μ? How would you calculate the margin of error for an estimate of μ?
Briefly explain the meaning of an estimator and an estimate.
According to a Gallup poll conducted August 7–10, 2014, 48% of American workers said that they were completely satisfied with their jobs. Assume that this result is true for the current population
According to a Pew Research survey conducted in February 2014, 24% of American adults said they trust the government in Washington, D.C., always or most of the time. Suppose that this result is true
According to a Bureau of Labor Statistics release of March 25, 2015, statisticians earn an average of $84,010 a year. Suppose that the current annual earnings of all statisticians have the mean and
According to a Bureau of Labor Statistics release of March 25, 2015, statisticians earn an average of $84,010 a year. Suppose that the current annual earnings of all statisticians have the mean and
According to a 2014 Kaiser Family Foundation Health Benefits Survey released in 2015, the total mean cost of employer-sponsored family health coverage was $16,834 per family per year, of which
According to the American Time Use Survey results released by the Bureau of Labor Statistics on June 24, 2015, on a typical day, 65% of American men age 15 and over spent some time doing household

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