MA 260 MA260 STATISTICAL ANALYSIS I EXAMS 1-8 ANSWERS (2021) - ASHWORTH
Ashworth MA260 Statistical Analysis I Exams 1-8 Answers (2021)
Ashworth MA260 Statistical Analysis I Exam 1 Answers (2021)
1. When experimental units are people, they are sometimes called ________________.
2. Which one of the following data are discrete?
3. Determine which of the following describes quantitative data.
4. A radio talk show invites people to call in and state whether or not they think that sexual harassment in the work place is a common problem.
5. Of the televisions offered at an electronics store, 42% cost less than $500.00. Is this an example of statistic or a parameter?
6. Which of the following is the best description of a randomized experiment?
7. An experiment that tends to overestimate or underestimate the true value is said to be ______________.
8. The names of all 137 students in a professor's class are written on identical slips of paper, and the slips are placed into a large glass jar. Then, the professor selects 12 random slips from the jar. Identify the kind of sample that is being used.
9. A middle school student passes out leaflets to the adults at a school function. The leaflets ask the recipient to indicate whether they believe in anthropogenic global warming. The bottom of the leaflet indicates that the completed leaflet should be returned to the student. Identify the kind of sample that is being used.
10. In an experiment, the ______________ is what is measured on each experimental unit.
11. Choose the answer below that best completes the following statement.
12. In a survey of 1000 teenagers, 23% of them said they use tobacco products. Is this an example of statistic or a parameter?
13. Which of the following sample types should you always regard as unreliable?
14. Choose the answer below that best completes the following statement.
15. By visiting homes door-to-door, a municipality surveys all the households in 149 randomly-selected neighborhoods to see how residents feel about a proposed property tax increase. Identify the type of sample that is being used.
16. In an experiment, subjects are put into two categories according to sex, and then each subject is randomly assigned a treatment . This is an example of...
17. You ask your friends who they plan to vote for in the next congressional election. Based on their responses, you conclude that the candidate you favor cannot lose!
18. A small brew pub sent out questionnaires to a simple random sample of 250 customers asking whether they would like the brewery to include an imperial stout in their regular offerings. Of the 250 questionnaires, 12 were returned and 10 of those were in favor of including the stout. Specify the type of bias involved.
19. Which of the following is the best description of a double-blind experiment?
20. Determine which of the following describes ordinal data.
Ashworth MA260 Statistical Analysis I Exam 2 Answers (2021)
1. Classify the histogram as unimodal or bimodal.
2. The following table presents the purchase totals (in dollars) of a random sample of gasoline purchases at a convenience store.
3. Classify the histogram as skewed to the left, skewed to the right, or approximately symmetric.
4. The amounts 3 and 4 are compared. Which of the following graphical displays are the least misleading?
5. The following time-series plot presents the population growth (in percent) of a suburb of Atlanta, Georgia for each of the years 1990 through 2009. Estimate the amount by which the rate of growth changed from 1,995 to 2,004.
6. The following frequency distribution presents the frequency of passenger vehicles that pass through a certain intersection from 8:00 AM to 9:00 AM on a particular day.
7. Construct a dotplot for the following data.
8. The following table presents the rate of population growth of a suburb of Atlanta, Georgia for each of the years 1990 through 2009. Construct a time-series plot of the growth rate.
9. Thirty households were surveyed for the number of televisions in each home. Following are the results.
10. The following table presents the purchase totals (in dollars) of a random sample of gasoline purchases at a convenience store.
11. A sample of 200 high school students were asked how many hours per week they spend watching television. The following frequency distribution presents the results.
12. The following bar graph presents the average amount a certain family spent, in dollars, on various food categories in a recent year.
13. Following is a pie chart that presents the percentages spent by a certain household on its five largest annual expenditures. What percentage of the money spent was spent on food, housing, and utilities?
14. The following frequency distribution presents the frequency of passenger vehicles that pass through a certain intersection from 8:00 AM to 9:00 AM on a particular day.
15. The following time-series plot presents the population growth (in percent) of a suburb of Atlanta, Georgia for each of the years 1990 through 2009. Estimate the rate of growth in 1,999.
16. The following frequency distribution presents the frequency of passenger vehicles that pass through a certain intersection from 8:00 AM to 9:00 AM on a particular day.
17. Construct a dotplot for the following data.
18. The following table presents the purchase totals (in dollars) of a random sample of gasoline purchases at a convenience store.
19. Toy sales: The following graph presents the percent market share for the US Toy Retail Sales between brick and mortar toy sales and online sales for the years 2011-2015. Does the graph present an accurate picture of the differences in revenue from these two sources? Or is it misleading?
20. The following frequency distribution presents the weights in pounds (lb) of a sample of visitors to a health clinic.
Ashworth MA260 Statistical Analysis I Exam 3 Answers (2021)
1. A population has a mean and standard deviation Find the z-score for a population value of 13.
2. The following table presents the number of monthly users for the 7 most popular mobile apps.
3. The table below lists the populations, in thousands, of several rural western counties. What is the mean population?
4. The following data represent the ice cream flavor choices of 20 diners at a college cafeteria.
5. Find the median for the following data set:
6. Approximate the sample variance given the following frequency distribution.
7. Find the mean for the following data set:
8. For which of the following histograms is it appropriate to use the Empirical Rule?
9. The following data represent the total price, in dollars, of 20 randomly-selected gasoline purchases at a certain convenience store.
10. Find the sample standard deviation for the following data set:
11. A soft-drink bottling company fills and ships soda in plastic bottles with a target volume of 354 milliliters. The filling machinery does not deliver a perfectly consistent volume of liquid to each bottle, and the three quartiles for the fill volume are and
12. Find the mean for the following data set:
13. A survey found that the median number of calories consumed per day in a certain country was 3,304 and the mean was 3,204.9 calories. If a histogram were constructed for the data, would you expect it to be skewed to the right, to the left, or approximately symmetric?
14. Following are the closing prices (in dollars) of a certain stock for the past 20 trading days.
15. Find the mean for the following data set:
16. The mean salary of professional baseball players is $2.58 million with a standard deviation of 0.33. A new player is hired with a salary of $2.76 million. What is the z-score of this salary?
17. The following table presents the number of monthly users for the 7 most popular mobile apps.
18. A report states that the mean household income last year for a certain rural county was $46,200 and the median was $37,800. If a histogram were constructed for the incomes of all households in the county, would you expect it to be skewed to the right, to the left, or approximately symmetric?
19. For the data set below, find the 37th percentile.
20. Approximate the sample standard deviation given the following frequency distribution.
Ashworth MA260 Statistical Analysis I Exam 5 Answers (2021)
1. A survey asked 33,625 homeowners how many pets they owned. The results were as follows:
2. If P(A) = 0.33, find P(AC).
3. In a recent semester at a local university, 540 students enrolled in both General Chemistry and Calculus I. Of these students, 51 received an A in general chemistry, 59 received an A in calculus, and 30 received an A in both general chemistry and calculus.
4. A section of an exam contains two multiple-choice questions, each with three answer choices (listed "A", "B", and "C"). Assuming the outcomes to be equally likely, find the probability (as a reduced fraction) that at least one answer is "A". [Hint: List all the outcomes of the sample space first.]
5. There are 25 students in a sixth-grade class. On a cold winter day in February, many of the students had runny noses and sore throats. After examining each student, the school nurse constructed the following table:
6. So far this season, the university's football team has executed 146 running plays, 167 passing plays, and 22 "trick" plays. What is the probability that the team will execute a passing play?
7. A survey asked 31,156 homeowners how many pets they owned. The results were as follows:
8. The probability that a certain make of car will need repairs in the first six months is 0.4. A dealer sells seven such cars. What is the probability that at least one of them will require repairs in the first six months?
9. A geneticist is studying two genes. Each gene can be either dominant or recessive. A sample of 100 individuals is categorized as follows.
10. Nanette must pass through three doors as she walks from her company's foyer to her office. Each of these doors may be locked or unlocked.
11. A survey asked respondents to indicate their level of satisfaction with government spending.
12. A poll was taken of 14,360 working adults aged 40-70 to determine their level of education. The participants were classified by sex and by level of education. The results were as follows.
13. A committee consists of 10 women and 7 men. Three members are chosen as officers. What is the probability that all three officers are women?
14. Assume a soldier is selected at random from the Army. Determine whether the events A and are independent, mutually exclusive, or neither.
15. If P(A) = 0.43, P(B) = 0.21, and P(A or B) = 0.64, are A and B mutually exclusive?
16. For the event described below, which of the following represents the complement of the event?
17. If P(A) = 0.69, P(B) = 0.4, and P(A or B) = 0.73, are A and B mutually exclusive?
18. What is the correct relationship between events A and B?
19. There are 25 students in a sixth-grade class. On a cold winter day in February, many of the students had runny noses and sore throats. After examining each student, the school nurse constructed the following table:
20. Nanette must pass through three doors as she walks from her company's foyer to her office. Each of these doors may be locked or unlocked.
Ashworth MA260 Statistical Analysis I Exam 6 Answers (2021)
1. The weights of 6-week-old poults (juvenile turkeys) are normally distributed with a mean 9.0 pounds and standard deviation 2.5 pound(s). Find the 75th percentile of the weights.
2. Find the shaded area under the standard normal curve.
3. The mean number of pets per household is 3.33 with standard deviation 1.6. A sample of 53 households is drawn. Find the 78th percentile of the sample mean.
4. A survey reported that in a recent year, the mean serum cholesterol level in milligrams per deciliter for U.S. adults was 199 with a standard deviation of 44. A random sample of 104 adults was chosen. What is the probability that the mean cholesterol level is less than 198?
5. Use technology to solve the following problem: The lifetime of a certain type of automobile tire (in thousands of miles) is normally distributed with mean μ = 40 and standard deviation σ = 6. What proportion of tires have lifetimes greater than 32 thousand miles?
6. Use the normal approximation to find the indicated probability. The sample size is n, the population proportion of successes is p, and X is the number of successes in the sample.
7. Use technology to solve the following problem: A ferry will safely accommodate 79 tons of passenger cars. Assume that the mean weight of a passenger car is 1.9 tons with standard deviation 0.5 tons. If a random sample of 39 cars are loaded onto the ferry, what is the probability that the maximum safe weight will be exceeded?
8. A gardener buys a package of seeds. Eighty-three percent of seeds of this type germinate. The gardener plants 90 seeds. Approximate the probability that fewer than 85 seeds germinate.
9. A bottler of drinking water fills plastic bottles with a mean volume of 998 milliliters (mL) and standard deviation The fill volumes are normally distributed. What proportion of bottles have volumes between and
10. The following figure is a probability density curve that represents the lifetime, in months, of a certain type of laptop battery.
11. A certain car model has a mean gas mileage of 34 miles per gallon (mpg) with a standard deviation A pizza delivery company buys 54 of these cars. What is the probability that the average mileage of the fleet is between 33.3 and
12. Find the area under the standard normal curve that lies between z = 0.5 and
13. According to a recent study, the weight of male babies less than two months old in the United States is normally distributed with mean 12.0 pounds and standard deviation 2.4 pounds. What proportion of babies weigh less than 9.1 pounds?
14. Using technology, use the Central Limit Theorem to find the indicated probability. The sample size is n, the population proportion is p, and the sample proportion is .
15. A gardener buys a package of seeds. Seventy-six percent of seeds of this type germinate. The gardener plants 120 seeds. Approximate the probability that the number of seeds that germinate is between 84.2 and 94.2 exclusive.
16. Use technology to solve the following problem: The mean annual income for people in a certain city (in thousands of dollars) is 44, with a standard deviation of 35. A pollster draws a sample of 59 people to interview. What is the probability that the sample mean income is between 42 and 48 (thousands of dollars)?
17. The following histograms each illustrate a sample. Which sample can be treated as approximately normal?
18. Use technology to solve the following problem: A normal population has a mean μ = 28 and standard deviation What proportion of the population is between 18 and 26?
19. For a particular diamond mine, 78% of the diamonds fail to qualify as "gemstone grade". A random sample of 106 diamonds is analyzed. Find the mean μ.
20. Using technology, use the normal approximation to find the indicated probability. The sample size is n, the population proportion of successes is p, and X is the number of successes in the sample.
Ashworth MA260 Statistical Analysis I Exam 8 Answers (2021)
1. A fleet of rental cars - all the same make, model, and year - has a mean fuel efficiency of 23.4 miles per gallon (mpg). A random sample of 41 cars are selected and the air filter of each is replaced with a new one. Let μ be the population mean fuel efficiency score that would occur if every car's air filter were replaced. The air filter change is deemed effective if . A test is made of versus .
2. In a simple random sample of size 88, there were 22 individuals in the category of interest. It is desired to test H0: p = 0.31 versus H1: p < 0.31. Compute the test statistic z.
3. In a simple random sample of size 75, there were 19 individuals in the category of interest. It is desired to test versus . Do you reject H0 at the 0.01 level?
4. In a study to determine whether counseling could help people lose weight, a sample of people experienced a group-based behavioral intervention, which involved weekly meetings with a trained interventionist for a period of six months. The following data are numbers of pounds lost for 14 people.
5. A test of versus is performed using a significance level of . The value of the test statistic is . Is H0 rejected?
6. A grocery store owner claims that the mean amount spent per checkout is more than . A test is made of H0: μ = 85 versus H1: μ > 85. The null hypothesis is not rejected. State the appropriate conclusion.
7. Use technology to find the P-value for the following values of the test , sample , and alternate hypothesis H1.
8. In a simple random sample of 77 families, the mean number of children is 2.2 with a standard deviation of 0.9. You wish to determine if the population mean differs from 2.1 children per family.
9. Find the critical value for the following values of the significance , sample , and alternate hypothesis H1.
10. The following display from a TI-84 Plus calculator presents the results of a hypothesis test for a population proportion p.
11. A sample of 39 students enroll in a program that claims to improve scores on the quantitative reasoning portion of the Graduate Record Examination (GRE). The participants take a mock GRE test before the program begins and again at the end to measure their improvement.
12. A market research firm reported that the mean annual earnings of all family practitioners in the United States was $179,574. A random sample of 38 family practitioners in New York that month had mean earnings of = $198,513 with a standard deviation of $35,113. You wish to test whether family practitioners in New York make more than the national average.
13. The Golden Comet is a hybrid chicken that is prized for its high egg production rate and gentle disposition. According to recent studies, the mean rate of egg production for 1-year-old Golden Comets is 5.6 eggs/week.
14. The following display from a TI-84 Plus calculator presents the results of a hypothesis test for a population mean μ.
15. The following output from MINITAB presents the results of a hypothesis test.
16. The following display from a TI-84 Plus calculator presents the results of a hypothesis test for a population mean μ.
17. The mean annual tuition and fees for a sample of 8 private colleges was with a standard deviation of . A dotplot shows that it is reasonable to assume that the population is approximately normal. You wish to test whether the mean tuition and fees for private colleges is different from .
18. The following output from MINITAB presents the results of a hypothesis test for a population mean μ.
19. The following output from MINITAB presents the results of a hypothesis test.
20. In a simple random sample of size 98, there were 37 individuals in the category of interest. Compute the sample proportion .
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