Questions and Answers of Basic Statistics In Business And Economics 10th

Find last season’s NFL team statistics. Construct a table showing the following for each team: number of wins, average yards gained on offense per game, and average yards allowed on defense per
Select a sample of at least eight people and measure each person’s height and arm span. (When you measure arm span, the person should stand with arms extended like the wings on an airplane.) Using
Select a sample of at least eight people and record each person’s pulse rate by counting the number of heartbeats in 1 minute. Also record each person’s height. Using the paired sample data,
Find a recent news report that discusses some type of correlation. Describe the correlation. Does the article give any sense of the strength of the correlation? Does it suggest that the correlation
Give examples of two variables that you expect to be positively correlated. Explain why the variables are correlated and why the correlation is (or is not) important.
A set of paired sample data results in a correlation coefficient of r = 0, so the scatterplot will show that there is no pattern of the plotted points.For Exercises 5–8, decide whether the
If we have 20 pairs of sample data with a correlation coefficient of 1, then we know that one of the two variables is definitely the cause of the other.For Exercises 5–8, decide whether the
If we conduct a study showing that there is a strong negative correlation between resting pulse rate and amounts of time spent in rigorous exercise, we can conclude decreases in resting pulse rates
If we have two variables with one being the direct cause of the other, then there may or may not be a correlation between those two variables.For Exercises 5–8, decide whether the statement makes
Statistics students find that as they spend more time studying, their test scores are higher.Exercises 9–16 make statements about a correlation. In each case, state the correlation clearly. (For
Astronomers have discovered that, with the exception of a few nearby galaxies, all galaxies in the universe are moving away from us. Moreover, the farther the galaxy, the faster it is moving away.
Find data for recent years concerning the Super Bowl winner and the end-of-year change in the stock market (positive or negative). Do recent results still agree with the correlation? Explain.
a. Describe a real situation in which there is a positive correlation that is the result of coincidence.b. Describe a real situation in which there is a positive correlation that is the result of a
r2 Value. A value of r2 = 1 is obtained from a sample of paired data with one variable representing the amount of gas (gallons) purchased and the total cost of the gas.For Exercises 5–8, decide
r2 Value. A value of r2 = -0.040 is obtained from a sample of men, with each pair of data consisting of the height in inches and the SAT score for one man.For Exercises 5–8, decide whether the
Using data from the National Health Survey, the equation of the best-fit line for women’s heights and weights is obtained, and it shows that a woman 120 inches tall is predicted to weigh 430
Use the scatterplot for color and price in Figure 2.For Exercises 9–12, do the following.
Use the data in Exercise 19 of Section 1.Exercises 13–20 refer to the tables in the Section 1 Exercises. In each case, do the following.
Use the data in Exercise 21 of Section 1.Exercises 13–20 refer to the tables in the Section 1 Exercises. In each case, do the following.
Use the data in Exercise 23 of Section 1. To locate the points, use the midpoint of each income category; use a value of $$25,000$ for the category “less than $$30,000$,”and use a value of
Use the data in Exercise 25 of Section 1 Exercises 13–20 refer to the tables in the Section 1 Exercises. In each case, do the following.
The following table gives five population indicators for eleven selected countries. Study these data and try to identify possible correlations. Doing additional research if necessary, discuss the
Figure 4 shows two distributions: (a) a famous data set of the chest sizes of 5,738 Scottish militiamen collected in about 1846 and (b) the distribution of the population densities of the 50 states.
Look again at the normal distribution in Figure 5.a. Estimate the percentage of births occurring between 0 and 60 days after the due date.b. Estimate the percentage of births occurring between 14
Which of the following variables would you expect to have a normal or nearly normal distribution?a. Scores on a very easy testb. Shoe sizes of a random sample of adult womenc. The number of apples in
The tests that make up the verbal (critical reading) and mathematics parts of the SAT (and the GRE, LSAT, and GMAT) are designed so that their scores are normally distributed with a mean of m = 500
Vending machines can be adjusted to reject coins above and below certain weights. The weights of legal U.S. quarters have a normal distribution with a mean of 5.67 grams and a standard deviation of
Consider again the question of whether you should advise a pregnant friend to schedule an important business meeting 2 weeks before her due date. Actual data suggest that the number of days between
You measure your resting heart rate at noon every day for a year and record the data. You discover that the data have a normal distribution with a mean of 66 and a standard deviation of 4.On how many
The Stanford-Binet IQ test is scaled so that scores have a mean of 100 and a standard deviation of 16. Find the standard scores for IQs of 85, 100, and 125.
Cholesterol levels in men 18 to 24 years of age are normally distributed with a mean of 178 and a standard deviation of 41.a. What is the percentile for a 20-year-old man with a cholesterol level of
IQ scores are normally distributed with a mean of 100 and a standard deviation of 16. What are the IQ scores for people in the 75th and 40th percentiles on IQ tests?
The heights of American women ages 18 to 24 are normally distributed with a mean of 65 inches and a standard deviation of 2.5 inches. In order to serve in the U.S. Army, women must be between 58
You are a middle school principal and your 100 eighth-graders are about to take a national standardized test. The test is designed so that the mean score is m = 400 with a standard deviation of s =
The mean salary of the 9,000 employees at Holley Inc. is m = +26,400 with a standard deviation of s = +2,420. A pollster samples 400 randomly selected employees and finds that the mean salary of the
The rate of unemployment has statistical significance because it has such a strong effect on the economy.For Exercises 5–8, decide whether the statement makes sense (or is clearly true) or does not
In an experiment testing a method of gender selection, 1,000 couples give birth to 550 girls and 450 boys. Because the probability of getting such extreme results by chance is only 0.0009, the
In a test of a technique of gender selection, the 100 babies born consist of at least 80 girls. Because there is about 1 chance in a billion of getting at least 80 girls among 100 babies, the results
In a survey, 50 students are randomly selected among all college students currently taking a statistics course, and it is found that they are all females.For each event in Exercises 9–16, state
In a pre-election survey, 100 likely voters are randomly selected from adults in the United States, and it is found that 6% of them are Democrats.For each event in Exercises 9–16, state whether the
In 6 rolls of a six-sided die, the outcome of 6 never occurs.For each event in Exercises 9–16, state whether the difference between what occurred and what you would have expected by chance is
A common lottery game is to select four digits, each between 0 and 9 (inclusive). Winning requires that you get the same four digits that are drawn, and they must be in the same order. You select
In conducting a survey of adults in the United States, a pollster claims that he randomly selected 20 subjects and all of them were women.For each event in Exercises 9–16, state whether the
A commuter enters a New York City subway car near Times Square and finds that it is occupied by 50 men, all of whom are bald.For each event in Exercises 9–16, state whether the difference between
For a trial on a charge of failure to pay child support, the jury consists of exactly 6 men and 6 women.For each event in Exercises 9–16, state whether the difference between what occurred and what
In a clinical trial of a new drug intended to treat allergies, 5 of the 80 subjects in the treatment group experienced headaches, and 8 of the 160 subjects in the control group experienced
A study of 75 students who took an SAT preparation course (American Education Research Journal, Vol. 19, No. 3) concluded that the mean improvement on the SAT was 0.6 point. If we assume that the
A National Health Survey determined that the mean weight of a sample of 804 men ages 25 to 34 years was 176 pounds, while the mean weight of a sample of 1,657 men ages 65 to 74 years was 164 pounds.
The cumulative frequency of a category in a table is 25.5.Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
The registered voters of Rochester County are 25% Democrats, 25% Republicans, and 50% independents. Construct a pie chart to represent the party affiliations. Registered Voters in Rochester County
Many states have lotteries that involve the random selection of digits 0, 1, 2, …,
Is the distribution of those digits a normal distribution? Why or why not?
Birth weights in the United States are normally distributed with a mean (in grams) of 3420 g and a standard deviation of 495 g. If you graph this normal distribution, the area to the right of 4000 g
A sample of 2,000 women is randomly selected, and it is found that the heights of the women are normally distributed with a mean of 63.6 in.Decide whether the statement makes sense (or is clearly
As part of a study of the relationship between brain size and IQ, a random sample of 250 adult males is obtained and their brain volumes are measured and found to be normally distributed.Decide
An economist plans to obtain the current salaries of all professional football players, and she predicts that those salaries will have a normal distribution.Decide whether the statement makes sense
The numbers selected in the Pennsylvania “Match 6” lottery, in which players attempt to match six randomly selected numbers between 1 and 49.State whether you would expect it to be normally
The lengths of time that commercial aircraft are delayed before departing.State whether you would expect it to be normally distributed. Explain your reasoning.
The waiting times at a bus stop if the bus comes once every 10 minutes and you arrive at random times.State whether you would expect it to be normally distributed. Explain your reasoning.
Figure 9 shows a histogram for the pulse rates of 98 students. The mean pulse rate is 71.2 beats per minute. Is this distribution close to normal? Should this variable have a normal distribution? Why
Figure 10 shows a histogram for the weights of 50 randomly selected quarters. The mean weight is 5.62 grams. Is this distribution close to normal? Should this variable have a normal distribution? Why
Consider the graph of the normal distribution in Figure 14, which illustrates the relative frequencies in a distribution of systolic blood pressures for a sample of female students. The distribution
Using the guidelines given in the text, choose a variable that you think should be nearly normally distributed. Collect at least 30 data values for the variable and make a histogram. Comment on how
Men’s heights are normally distributed with a mean of 69.0 in. and a standard deviation of 2.8 in. What is the standard z-score for a man with a height of 69.0 in.?
The standard score for the height of a male is z = -2. Is the height of this male above or below the mean height of all males? How many standard deviations away from the mean is this?
For rolling a die, the mean outcome is 3.5. Can we apply the 68-95-99.7 rule and conclude that 95% of all outcomes fall within 2 standard deviations of 3.5? Why or why not?
Birth weights (in grams) in Lichtenstein are normally distributed with a mean of 3,420 g and a standard deviation of 0 g.Decide whether the statement makes sense (or is clearly true) or does not make
Scores on a standard test of depth perception are normally distributed with two different modes.Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly
SAT scores are normally distributed with a mean of 1518 and a standard deviation of 325.Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false).
Percentage of scores greater than 148 Use the normal distribution of IQ scores, which has a mean of 100 and a standard deviation of 16. Use Table 1 to find the indicated quantities. Note: Table 1
Percentage of scores between 76 and 108 Table 1 to find the indicated quantities. Note: Table 1 shows standard scores from -3.5 to +3.5. In these problems, for standard scores above 3.5, use a
The percentage of heights greater than 162 centimeters
The percentage of heights less than 168 centimeters
The percentage of heights greater than 156 centimeters
The percentage of heights greater than 171 centimeters
The percentage of heights less than 177 centimeters
The percentage of heights less than 147 centimeters
The percentage of heights less than 144 centimeters
The percentage of heights greater than 179 centimeters
The percentage of heights between 156 centimeters and 168 centimeters
The percentage of heights between 159 centimeters and 165 centimeters
The percentage of heights between 148 centimeters and 170 centimeters
The percentage of heights between 146 centimeters and 156 centimeters
In this section, it was noted that the standard deviation of sample means is s/1n. In that expression, what does s represent and what does n represent?
The population of unemployed adults has ages with mean m and standard deviations. Samples of unemployed adults are randomly selected so that there are exactly 100 in each sample. For each sample, the
In the United States, there are many people with little or no accumulated wealth, and there are a few people with very large amounts of wealth. What does this suggest about the symmetry of the
When the digits 0 through 9 are selected for a state lottery, the digits are selected in a way that they are all equally likely. Which term best describes the distribution of selected digits:
What is skewness in a graph?
Because a data set has three modes, it must have a skewed distribution.Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
Examination of the data set reveals that it is symmetric with a mean of 98.2 and a median of 98.2.Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly
Examination of a data set reveals that its distribution is left-skewed and unimodal.Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain
Examination of a data set reveals that the mean and median are both equal to 98.2, so the distribution must be uniform.Decide whether the statement makes sense (or is clearly true) or does not make
The histogram in Figure 9 shows the times between eruptions of Old Faithful geyser in Yellowstone National Park for a sample of 300 eruptions (with 299 times between eruptions). Over the histogram,
The histogram in Figure 10 shows the time until failure for a sample of 108 computer chips. Over the histogram, draw a smooth curve that captures its general features. Then classify the distribution
The histogram in Figure 11 shows the weights of a sample of 391 rugby players. Over the histogram, draw a smooth curve that captures its general features. Then classify the distribution according to
In a recent year, the 817 professional baseball players had salaries with the following characteristics: • The mean was $$3,250,178$. • The median was $$1,152,000$. • The salaries ranged
The heights of 500 male students, half of whom are adults while the other half are eight years of age.Answer the following questions: a. How many modes would you expect for the distribution? b.
The weights of the cola in 1000 randomly selected cans of Coke.Answer the following questions: a. How many modes would you expect for the distribution? b. Would you expect the distribution to be
The weights of cars in a fleet consisting of 50 compact cars and 50 delivery trucks.Answer the following questions: a. How many modes would you expect for the distribution? b. Would you expect the
The ages of 1,000 randomly selected patients being treated for dementia.Answer the following questions: a. How many modes would you expect for the distribution? b. Would you expect the distribution

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