stats final exam practice problems

The following stem and leaf plot shows the annual salaries of a company's executives rounded to the nearest ten thousand dollars (i.e., $210,000 - $850,000). What are the leaf units?

10.,000

A boxcar lot of ball bearings has an average diameter of 2.503 centimeters (cm). This is within the specifications for acceptance of the lot by the purchaser. The inspector happens to inspect 100 bearings from the lot with an average diameter of 2.515 cm. This is outside the specified limits, so the lot is rejected. What is the sample size?

100

The following stem and leaf plot shows the annual salaries of a company's executives rounded to the nearest ten thousand dollars (i.e., $210,000 - $850,000). What are the stem units?

100,000

Attached are the summary statistics for the data set containing the ages of the Oscar winning best actresses. What is the IQR for winning actresses' ages? (NEED PHOTO)

12

Given a population of size N=93, use Row 29 of Table E1, the Random Digit Table, to select a sample of 10 with replacement.

12, 47, 83, 76, 22, 65, 93, 10, 65, 83

Given a population of size N=93, use Row 29 of Table E1, the Random Digit Table, to select a sample of 10 without replacement.

12, 47, 83, 76, 22. 65, 93, 10, 61, 36

I love lots of pizza combinations. I could eat it every day. How many different pizzas can I create from the following choices? 1 Crust: Three (3) crusts, choose one (1). 1 Sauce: Three (3) sauces, choose one (1). 4 Meats: Ten (10) meats, choose four (4). 2 Vegetables: Twelve (12) vegetables, choose two (2).

124,740

I have too many shoes! I have 20 pairs of sandals. But I can only take 5 pair on vacation. How many different sets could I choose?

15,504

If the standard deviation for the data set is 4, the variance is _____

16

The correlation between two variables x and y is r = 0.4. If we used a regression line to predict y using x, what percent of the variation in y would be explained by the linear regression of y on x?

16%

During the most recent economic recession, the auto industry relied heavily on 0% financing to entice customers to purchase cars. Edmonds.com estimated that 22.4% (0.224) of the car deals involved 0% financing. A random sample of 500 financed car deals found that 98 of them used 0% financing. Construct a 99% confidence interval estimate for the population proportion of car deals that used 0% financing.

(0.1502, 0.2418)

A survey is being conducted using a random sample of 150 economists, asking whether paying off debt is the best usage of federal stimulus funds by the state. Of those, 43 think it is the best usage of the funds, and 107 think it is not. The true percentage of all economists thinking it is the best usage is 30%. Find the standard deviation of the sampling distribution of the proportions for a sample of size 150 of those that think paying off debt is the best use of funds.

0.0374

The weight of National Football League (NFL) players has increased steadily, gaining up to 1.5 lb. per year since 1942. According to ESPN, the average weight of a NFL player is now 245.86 lb. Assume the population standard deviation is 32 lb. If a random sample of 50 players is selected, what is the probability that the sample mean will be more than 252 lb.?

0.0869

The probability that a standard normal variable, Z, is in the interval(0,1.0) is approximately:

0.3400

Ice cream consumption was measured over 30 four-week periods from March 18, 1951 to July 11, 1953. The purpose of the study was to determine if ice cream consumption depends on the variables price, income, or temperature. For this HW question, we want to see if the temperature (temp) affects the ice cream consumption (IC). Attached is the output from the simple linear regression of temperature on ice cream consumption. What is the predicted ice cream consumption when it's 65 degrees?

0.4084

Attached is a histogram of the ages of actors and actresses who won the Oscar for Best Actor and Actress from 1928 through 2007. Approximate the proportion of winning actresses who were [30, 40) years of age when they won. (NEED PHOTO)

0.41

A traffic control engineer reports that 75% of the vehicles passing through a checkpoint are from within the state. What is the probability that fewer than 2 of the next 5 vehicles are from out of state? (Round to 4 decimal places)

0.6328

There are 34 students in your statistics section. You want to choose an SRS of 3 of these students. A correct way to assign labels to the 34 students before using the random digit table is

00, 01, 02, ..., 33. 01, 02, 03, ..., 34 (only (a) and (c) are true)

A Professional Business Fraternity is selecting officers for President, Vice President, Secretary and Treasurer. There are 36 members in the fraternity. Each member is eligible for each position, but no member can hold two positions. In how many ways can the officers be chosen?

1,413,720

Given the summary statistics in the table below, Calculate the Standard Score for x = 50. Z = ____________

1.8

Use the attached relative frequency histogram to approximate the percentage of students that are 70 inches tall or taller. (NEED PHOTO)

22%

Attached are the summary statistics for the data set containing the ages of the Oscar winning best actresses. What percentage of winning actresses were 28.5 years old or younger? (NEED PHOTO)

25

A boxcar lot of ball bearings has an average diameter of 2.503 centimeters (cm). This is within the specifications for acceptance of the lot by the purchaser. The inspector happens to inspect 100 bearings from the lot with an average diameter of 2.515 cm. This is outside the specified limits, so the lot is mistakenly rejected. What is the value of the statistic?

2.515

There are 32 NFL teams. Their record determines the order in which they will draft new players for the next season. How many different arrangements exist for the draft order for these 32 teams (assume there are no trades)?

2.6313*10^35

When I look in my closet, I have 6 pair of blue jeans, 2 pair of black jeans, 1 pair of white jeans, 5 pair of black pants, 1 pair of navy pants, 3 pair of brown pants and 2 pair of khaki pants. If I randomly select one pair of pants to wear today, what is the probability they will be khaki?

2/20

You want to take an SRS of 50 of the 250 students who live in a college dormitory. You label the students 000 to 249 in alphabetical order. Using the following line from the table of random digits, find the first three students in your sample. 96746 12149 37823 71868 18442 35119 62103 23924

214, 235, 119

Attached are the summary statistics for the data set containing the ages of the Oscar winning best actresses. What percentage of winning actresses were 40.5 years old or older? (Give answer as a whole number w/o the percent sign). (NEED PHOTO)

25

Attached are the summary statistics for the data set containing the ages of the Oscar winning best actresses. 50% of the winning actresses were _____ years of age or older. (NEED PHOTO)

34

A lock has 6 numbers and will unlock with the proper four-number sequence. How many possible combinations exist?

360

Suppose that at a university with 25,000 students the amount of money spent by the students on books each semester is approximately normally distributed with a mean of $250 and standard deviation of $50. About how many of the students spend less than $200 on books?

4,000

A team is being formed that includes eight different people. There are eight different positions on the teams. How many different ways are there to assign the eight people to the eight positions?

40,320

Five parts are selected for inspection from a large shipment of parts. The parts are labeled 01 through 50. Use the random digits below to select the five unique parts for inspection. 66925 39550 78458 11206 19876 87151 31260 52421

50, 45, 12, 06, 19

There is a small restaurant near my home. The menu carries 8 appetizers, 7 entrees, and 3 deserts, plus 3 drinks. If my meal consists of one appetizer, one entree, one desert and one drink, how many different meals can I order?

504

Attached are the summary statistics for the data set containing the ages of the Oscar winning best actresses. What is the range for winning actresses' ages? (NEED PHOTO)

59

When I go to a coffee shop I have lots of options! Coffee or tea Milk: no milk, whole milk, 2% milk, fat free milk, almond milk, soy milk Syrup: None, Chocolate, Vanilla, Raspberry, Hazelnut What is the total number of possible drinks I could order?

60

Ice cream consumption was measured over 30 four-week periods from March 18, 1951 to July 11, 1953. The purpose of the study was to determine if ice cream consumption depends on the variables price, income, or temperature. For this HW question, we want to see if the temperature (temp) affects the ice cream consumption (IC). Attached is the output from the simple linear regression of temperature on ice cream consumption. What percentage of change in ice cream consumption can be explained by temperature? (NEED PHOTO)

60.16%

Use the attached relative frequency bar chart to determine the approximate pecentage of students in class who are from South Carolina. (NEED PHOTO)

65%

Attached is a pie chart of movie preference. How big is the central angle of the "Comedy" wedge? (NEED PHOTO)

72 degrees

A researcher for a fast food restaurant is timing how long it takes for an order to be delivered to a customer at a walk up counter. The following stem and leaf plot shows the time in minutes that it takes to deliver the order. The minimum time is 2.1 minutes.

8.5 minutes

Attached are the summary statistics for the data set containing the ages of the Oscar winning best actresses. How many actresses' ages have been recorded? (NEED PHOTO)

80

A set of final examination grades in a statistics course is normally distributed, with a mean of 73 and a standard deviation of 8. The probability is 5% that a student taking the test scores higher than what grade. (Use Z-Table)

86

Use the attached bar graph to determine how many students are ambidextrous. (NEED PHOTO)

9

One of the following 12 scores (84 76 92 96 88 96 68 80 92 88 76 96) was omitted from the stemplot below: (NEED PHOTO)

96

Harley-Davidson motorcycles reportedly make up 30% of all motorcycles registered in the United States. You think that is an overstatement. You interview a random sample of 600 motorcycle owners and find that 28% of them own Harleys.The Hypotheses are:

H0: p 0.30 H1: p 0.30

The following table contains the probability distribution for the number of traffic accidents daily in a town. (Round answers to 2 decimal places) a. What is the Probability there will be one (1) accident on a given day? b. What is the Expected Number of accidents per day? c. What is the Standard Deviation of the number of accidents per day? d. What is the Probability that there will be at least two (2) accidents on a given day?

a. 0.34 b. 1.53 c. 1.51 d. 0.38

Here are two opinion poll questions asked in 2017 about stem cell research." Do you support or oppose embryonic stem cell research?"" All in all, which is more important: conducting stem cell research that might result in new medical cures, or not destroying the potential life of human embryos involved in this research?" In response to the first question, 61% supported stem cell research. But only 51% of those asked the second question thought conducting stem cell research was more important. Why do you think the second wording discouraged more people from supporting stem cell research?

The phrase "not destroying the potential life of human embryos" may have brought negative images to mind, which overshadowed the phrase "might result in medical cures."

Recordable injuries are defined by the Occupational Safety and Health Administration (OSHA) as injuries to employees that require medical treatment beyond routine first aid. Assume the number of recordable injuries each month follows a Poisson distribution with an average of 1.8 injuries per month. Round answers to four decimal places. A) What is the probability that exactly two recordable injuries will occur next month? B) What is the standard deviation of the number of recordable injuries per month?

a. 0.2678 b. 1.3416

If you draw an M&M at random from a bag of the candies, the piece you draw will be one of six colors: brown, red, yellow, green, orange, tan. The probability of drawing each color depends on the proportion of each color among all candies made. Assume the attached table gives the probability model for the color of a randomly chosen M&M. (NEED PHOTO) a. The probability of drawing a red candy is _____. b. The probability of NOT drawing a tan candy is _____. c. The probability of drawing EITHER a red or a tan candy is _____.

a. 0.3 b. 0.9 0.4

According to the Internal Revenue Service, the average income tax refund last year for the 2022 tax year was $3,012, approximately 8.6% more than this year in 2023. Assume the refund per person follows the normal probability distribution with a standard deviation of $760. Note: Use the Normal Z Table (E2). Round answers to 4 decimal places. A) What is the probability that a randomly selected tax return refund last tax year will be less than $2,000? B) What is the probability that a randomly selected tax return refund last tax year will be more than $4,000? C) What is the probability that a randomly selected tax return refund last tax year will be between $2,000 and $4,000?

a. 0.0918 b. 0.096 c. 0.8122

Given a Standard Normal Distribution (with mean 0 and standard deviation 1), determine the following probabilities. Round all answers to 4 decimal places. a. P(Z > 1.07) [a] b. P(Z < -0.25) [b] c. P(-1.96 < Z < -0.25) [c]

a. 0.123 b. 0.4013 c. 0.3763

Many wholesale stores offer free samples for customers to taste things in order to increase sales. Let's assume that Costco provides free samples of cheese for everyone who walks by the cheese aisle. Historically, 35% of the customers who sampled a product purchased it. A) What is the probability exactly 10 of the next 25 customers who taste the cheese will purchase? B) What is the expected number of these 25 customers to purchase? C) What is the standard deviation of the number of purchases?

a. 0.141 b. 8.75 c. 2.38

Suppose that a computer programmer, on average, makes 3 errors in 500 lines of code. a. What is the probability that the programmer will make no errors in 250 lines of code? [a] (Round to 4 decimal places) b. What is λ, the expected number of errors in 250 lines of code? [b] (Round to 1 decimal place)

a. 0.2231 b. 1.5

A political committee consists of eight (8) Democrats and four (4) Republicans. A subcommittee of six (6) unique people needs to be formed. A) Determine the probability that one Republican will be on the subcommittee if it is randomly selected. B) Determine the probability that at least one Republican will be on the subcommittee if it is randomly selected. C) Calculate the mean for the distribution which defines selecting a Republican as a success. D) Calculate the standard deviation for the distribution which defines selecting a Republican as a success.

a. 0.2424 b. 0.969 c. 2 d. 0.85

The manager of the mortgage department in a large bank collected data to determine the number of mortgages approved per week. The following table shows the probability distribution for his data. a. What is the probability the bank will approve less than 2 mortgages per week? b. What is the probability the bank will approve at least 2 mortgages per week? c. What is the Expected number of mortgages approved per week? [c]

a. 0.25 b. 0.75 c. 2.78

A psychologist thinks that listening to Mozart helps people think. She gives subjects a set of puzzles and measures how many they solve in 5 minutes while listening to Mozart. From data on a very large number of simulations, the psychologist gets the following probability distribution. a. What is the probability that a subject solves more than 2 puzzles? b. What is the probability that a subject solves at most 3 puzzles? c. What is the expected number of puzzles solved? d. What is the standard deviation of the number of puzzles solved ?

a. 0.35 b. 0.9 c. 2.25 d. 0.89

You are a financial analyst facing the task of selecting bond mutual funds to purchase for a client's portfolio. You have narrowed the funds to be selected to thirteen (13) different funds. In order to diversify your client's portfolio, you will recommend the purchase of three (3) different funds. Seven (7) of the funds are short-term corporate bond funds. Compute the following probabilities. a. What is the probability that of the three (3) funds selected, exactly one (1) is a short-term corporate bond fund? b. What is the probability that of the three (3) funds selected, at least one (1) is a short-term corporate bond fund?

a. 0.3671 b. 0.9301

There are 60 students in a class. 10 are graduate students. We form a committee by randomly choosing 5 unique students. a. What is the probability that there will be no graduate students on the committee? b. What is the expected number of graduate students on the committee?

a. 0.3879 b. 0.83

A business operates two shifts, Day and Night. Over the last year they have had 125 accidents. Some accidents are related to unsafe working conditions, others are unrelated to work conditions. The following contingency table shows the number of accidents by shift and work condition. Compute probabilities to four decimal places. a. What is the probability that an accident is due to Unsafe Conditions? [a] b. What is the probability that a randomly selected accident occured on the Night Shift? [b] c. What is the probability a randomly selected accident occured on Night Shift and was due to Unsafe Conditions? [c] d. What is the probability a randomly selected accident occured on Night Shift or was due to Unsafe Conditions? [d] e. What is the probability a randomly selected accident occured on Night Shift given it was due to Unsafe Conditions? [e] f. Are the events Night Shift and Unsafe Conditions mutually exclusive? [f

a. 0.4 b. 0.76 c. 0.304 d. 0.856 e. 0.76 f. no g. yes

The following contingency table shows the number of adults (120,628 in thousands) in a survey who were employed and unemployed in 2018 along with their education level. a. What is the probability that a randomly selected adult is a College Graduate? [a] b. What is the probability that a randomly selected adult is Unemployed? [b] c. What is the probability a randomly selected adult is a College Graduate and Unemployed? [c] d. What is the probability a randomly selected adult is a College Graduate or Unemployed? [d] e. What is the probability a randomly selected adult is Unemployed given they are a College Graduate. [e] f. Are the Events College Graduate and Unemployed mutually exclusive? [f] (Yes or No) g. Are the Events Unemployed and College Graduate independent? [g] (Yes or No)

a. 0.4551 b. 0.0320 c. 0.0136 d. 0.4735 e. 0.0299 f. no g. no

Past records indicate that the probability of online retail orders that turn out to be fraudulent is 0.04. Suppose that, on a given day, 20 online retail orders are placed. Assume that the number of online retail orders that turn out to be fraudulent is distributed as a binomial random variable. a. What is the mean number of online orders that will turn out to be fraudulent? [a] b. What is the standard deviation of the number of fraudulent retail orders? [b] c. What is the probability that zero (0) online retail orders will turn out to be fraudulent? [c] d. What is the probability that one (1) online retail order will turn out to be fraudulent? [d] e. What is the probability that two or more online retail orders will turn out to be fraudulent? [e]

a. 0.8 b. 0.8764 c. 0.442 d. 0.3683 e. 0.1897

The data table below represents a sample of data from the LakeLevels database for Lake Murray Water Levels in 2023. Data is given in Feet MSL. The full pool level is 360.00 feet. a. The sample size, n, is b. The Sum is c. The Mean is d. The Variance is e. The Standard Deviation f. The Median is g. The Range is h. Q1 is i. Q3 is j. The IQR is k. Using the IQR method, are there any outliers in the data? l. Is the data skewed? (Yes or No) Calculate the Z-score for the value m. 356.28

a. 10 b. 3523.59 c. 352.33 d. 4.85 e. 2.204 f. 351.95 g. 6.18 h. 350.26 i. 354.2 j. 3.94 k. no l. yes m. 1.79

For pigs, the length of pregnancies varies according to a normal distribution with a mean of 114 days and a standard deviation of 5 days. a. According to the Empirical Rule, the length of approximately 68% of all pig pregnancies will fall between _____ and _____ days. b. According to the Empirical Rule, approximately what percentage of pigs will have a pregnancy shorter than 109 days? c. According to the Empirical Rule, approximately 2.5% of all pig pregnancies will be longer than _____ days.

a. 109, 119 b. 16% c. 124

An Air Force intercept squadron consists of 16 planes that should always be ready for immediate launch. However, there is a probability of 0.25 that the engines of a particular plane will not start at a given attempt. If this happens, the mechanics must wait 5 minutes before trying to start the engine again. a. What is the expected number of planes to immediately launch? b. What is the standard deviation of the number of planes that immediately launch?

a. 12 b. 1.73

Albert Pujols joined the 700 Club for home run counts in September last year. He played Major League Baseball for 22 years starting in 2001. His HR counts are recorded below: a. Find the minimum. [a] b. Find the first quartile of homeruns. [b] c. Find the median number of homeruns. [c] d. Find the third Quartile of homeruns. [d] e. Find the maximum. [e]

a. 12 b. 23 c. 33 d. 41 e. 49

Using the Contengency Table below: A survey of [a] Americans adults were asked​ "Do you feel overloaded with too much​ information?" The results indicate that [b] percent (%) of females feel information overload compared to [c] percent (%) of males.

a. 1520 b. 82 c. 57

In 1995, the math SAT scores followed a normal distribution with mean 490 and standard deviation 50. In 1996, the math SAT scores followed a normal distribution with mean 510 and standard deviation 75. a. What is the standard score for a student scoring 600 in 1995? [a] b. What is the standard score for a student scoring 600 in 1996? [b] c. Relatively speaking, which student did better, 1995 or 1996? [c]

a. 2.2 b. 1.2 c. 1995

If SSR= 16 and SSE = 4, a. SST = b. the coefficient of​ determination is

a. 20 b. 0.8

Last year Airline A had 6.88 mishandled bags per 1,000 passengers. Let the random variable X be the # of mishandled bags. a. What is the expected value of X? b. What is the probability that in the next 1,000 passengers, the airline will have no mishandled bags? c. What is the probability that in the next 1,000 passengers, the airline will have at least one mishandled bag? d. What is the probability that in the next 1,000 passengers, the airline will have at least two mishandled bags?

a. 6.88 b. 0.0010 c. 0.9990 d. 0.9919

A consumer information website tracks automobile complaints. Their report contains consumer vehicle complaint submissions by​ automaker, brand, and category. The accompanying table represents complaints received by automaker. Compute the percentage of complaints for each automaker. a. 212 b. 430 c. 490 d. 561 e. 422 f. 216 g. 443 h. The automaker with the most complaints is automaker i. The automaker with the least complaints is automaker

a. 7.6 b. 15.5 c. 17.6 d. 20.2 e. 15.2 f. 7.8 g. 15.9 h. automaker D i. automaker A

A survey was conducted of STAT 206 students and they were asked their height in inches. The mean of the sample was 69.52 inches. The standard deviation of the sample was 4.1 inches. a. What is your height in inches? (Round to a whole number. Your answer must be between 60 and 80) b. Calculate the Z-score for your height. (Round to 2 decimal places) c. Is your height considered an extreme outlier? (Yes or No)

a. 70 b. 1 c. no

A Regression Analysis was conducted of Business Students who wanted to get their MBA. The Regresion Analysis shows the Verbal GMAT Entrance Exam score for each of 10 MBA students along with their grade point average (GPA) in undergraduate school. Output from a regression analysis follows: A. The slope of the line equals B. The y-intercept is C. Predict the GMAT score with a student who has a GPA of 3.6. D. The value of the correlation coefficient is

a. 79.33 b. 27.31 c. 312 d. 0.94

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for Medicaid. The ages of 11 senior citizens were as follows: 70 60 76 91 86 75 64 69 75 68 71 a. The Sum is b. The Mean is c. The Variance is d. The Standard Deviation is e. The Median is f. The Mode is g. The Range is h. Q1 is i. Q3 is j. The IQR is k. Using the IQR method, are there any outliers in the data? (Yes or No) l. Is the age data skewed? (Yes or No) m. Calculate the Z-score for the value 91. n. Using the Z-score method, is 91 an outlier? (Yes or No)

a. 805 b. 73.1 c. 81.3 d. 9.0 e. 71 f. 75 g. 31 h. 68 i. 76 j. 8 k. yes l. yes m. 1.9 n. no

Assume the distribution of annual income for a certain job follows a normal distribution with mean $50,000 and standard deviation $2,500. a. According to the Empirical Rule, approximately what percentage of workers in this job earn between $45,000 and $55,000 annually? b. Using the Z-Table, Table E.2, what percentage of people who have this job earn more than $55,000 annually? c. Using the Z-Table, Table E.2, 2.28% of the workers earn less than _____ annually.

a. 95% b. 2.28% c. $45k

A manufacturer says their football helmets have no more than 10% defects. A researcher claims that more than 10% (0.10) of all football helmets have manufacturing flaws that could potentially cause injury to the wearer. A sample of 300 helmets revealed that 36 helmets contained such defects. Test the researcher's claim using α = 0.05.\ a. Is the data categorical or quantitative? b. Is this a greater-than, less-than or not-equal test? c. What is the point estimate? d. What is (n)x(p-hat)? e. What is (n)x(1 - p-hat)? f. Is the sample size large enough to use Normal Approximation? (Yes or No) g. What is the test statistic? h. What is the p-value? i. Is there sufficient evidence to conclude that more than 10% of all football helmets have manufacturing defects. (yes or no) j. What is the 95% Lower Confidence Bound for the proportion of helmets with defects?

a. categorical b. greater c. 0.12 d. 36 e. 264 f. yes g. 1.15 h. 0.12 i. no j. 0.8

The Straits Times newspaper advertised the following diamonds. The prices of the ladies' diamond rings and the carat size of their diamond stones were analyzed. The rings are made with gold of 20 carats purity and are each mounted with a single diamond stone. Output from a regression analysis follows. $ Price = -259.52 + 3727.08(Carat Size) Sample size: 45R-sq = 0.975 Estimate of error standard deviation: 34.096104 A. The response variable is [a]. B. The slope of the line equals [b]. C. The value of the y-intercept is [c]. D. Predict the price of a ring if the carat size is one-quarter (0.25) carat. E. The value of the correlation coefficient is [e]. (Round to 3 decimal places

a. price b. 3727.08 c. -259.52 d. 672.25 e. 0.98

In 2019 the average credit score for mortgage loans purchased by Fannie Mae was 749. In 2022 a sample of 25 mortgages were randomly selected and it was found that the average credit score was 745 with a sample standard deviation of 24. Assume the data was normally distributed. Compute a 90% confidence interval for the 2022 average credit score. a. Is the data categorical or quantitative? [a] b. What is the point estimate? [b] c. What is the critical value? [c] (Round to 3 decimal places) d. What is the standard error? [d] (Round to1 decimal place) e. What is the Margin of Error? [e] (Round to 3 decimal places) f. Based on the 90% Confidence Interval for the 2022 average credit score, have the credit scores decreased since 2019? [f] (Yes or No) g. I would like to obtain a 90% Confidence interval using the data above, within 5. What sample size would I need? [g]

a. quantitative b. 745 c. 1.71 d. 4.8 e. 8.21 f. no g. 62

An Uber company claims that its average pick-up time is under 15 minutes. A sample of 50 riders was examined, and the average pick-up time was found to be 13.2 minutes. Historically the population standard deviation for pick-up time is 4.6 minutes. Test the company's claim using α=0.05. a. Is the data categorical or quantitative? b. Is the parameter a mean or a proportion? c. Is this a greater-than, less-than or not-equal test? d. What does the test statistic equal? e. What is the critical value? f. What is the p-value? g. Is there sufficient evidence to conclude the average pick-up time is under 15 minutes? (yes or no) h. If the true mean is 14 minutes, did we commit a Type I error, Type II error, or No error?

a. quantitative b. mean c. less d. -2.7 e. 1.6 f. 0.002 g. yes h. no

Ice cream consumption was measured over 30 four-week periods from March 18, 1951 to July 11, 1953. The purpose of the study was to determine if ice cream consumption depends on the variables price, income, or temperature. For this HW question, we want to see if the temperature (temp) affects the ice cream consumption (IC). Attached is the output from the simple linear regression of temperature on ice cream consumption. For every one degree increase in temperature, we expect ice cream consumption to __________. (NEED PHOTO)

increase by 0.0031 pints per capita

The General Social Survey (GSS), conducted by the National Opinion Research Center at the University of Chicago, is a major source of data on social attitudes in the United States. Every other year, approximately 3,000 American adults aged 18 and over are interviewed in their homes all across the U.S. The subjects are asked their opinions about sex and marriage, about their attitudes toward women, welfare, foreign policy and many other issues. The implied population is

all American adults aged 18 and older.

A Gallup Poll asked 1,002 randomly chosen adults to rate the "honesty and ethical standards" of 21 occupations. Nurses were at the top, with 82% of the poll respondents rating them "very high" or "high." Telemarketers were at the bottom with just 7% "very high" or "high" ratings. The population for this poll is

all adults

Watch the 60 Minutes episode about the Duke Clinical Trial. The Clinical Trial was for patients with __________.

all forms of cancer

Watch the 60 Minutes episode about the Duke Clinical Trial. The lie in Anil Potti, MD's application for grants involved __________.

an honorary award

Here are boxplots of the number of calories in 20 brands of beef hot dogs, 17 brands of meat hot dogs, and 17 brands of poultry hot dogs.

beef

The following stem and leaf plot shows the annual salaries of a company's executives rounded to the nearest ten thousand dollars (i.e., $210,000 - $850,000). the shape of the data is

binomial

Brian gathers data from his classmates about the computers they own such as the type of operating system, the amount of memory, and the year the computer was purchased. Who/what are the individuals in this data set?

brian's classmates

Here is a stemplot of the percent of males, 15 and older, who are illiterate in 139 countries, according to the United Nations. For example, the highest illiteracy rate was 69%, in the African country of Mali. (NEED PHOTO)

clearly skewed to the right

Watch the 60 Minutes episode about the Duke Clinical Trial. The fault in Anil Potti, MD's research was__________

dr. potti lied

Attached are the summary statistics for the data set containing the ages of the Oscar winning best actresses. It is more likely that a randomly chosen winning actress will be between 21 and 28.5 years old than between 40.5 and 80 years old. (NEED PHOTO)

false

You gather data on the number of hours of TV news broadcasts watched per week and the grade point average (GPA) of juniors majoring in journalism. You expect that TV news broadcast watching will help explain grades. The plot of the data shows that students who watch more TV news broadcasts tend to have higher GPAs. A plausible value for the correlation r between hours of TV and GPA is

r = 0.4

Ice cream consumption was measured over 30 four-week periods from March 18, 1951 to July 11, 1953. The purpose of the study was to determine if ice cream consumption depends on the variables price, income, or temperature. For this HW question, we want to see if the temperature (temp) affects the ice cream consumption (IC). Attached is the output from the simple linear regression of temperature on ice cream consumption. What is the value of the correlation coefficient, r? (NEED PHOTO)

r = 0.7756

Read Chapter 19, TM and Six Sigma. When companies apply the Six Sigma improvement strategies, high level success cannot be achieved without the leadership of the _______________________.

senior executive

For this histogram, which of the following is true: (left-skewed) (NEED PHOTO)

shewed left

Attached is a histogram of the ages of actors and actresses who won the Oscar for Best Actor and Actress from 1928 through 2007. Describe the shape of this distribution. (NEED PHOTO)

skewed to the right

The General Social Survey (GSS), conducted by the National Opinion Research Center at the University of Chicago, is a major source of data on social attitudes in the United States. Every other year, approximately 3,000 American adults aged 18 and over are interviewed in their homes all across the U.S. The subjects are asked their opinions about sex and marriage, about their attitudes toward women, welfare, foreign policy and many other issues. The GSS shows 26% of the sample think only married partners should have sex. The 26% is a __________.

statistic

The Shewhart-Deming Cycle represents a continuous cycle of Plan, Do, Study and Act. This cycle is now the basic format of the International Standards for Management. In which step of the cycle are statistical methods used?

study

The correlation between the heights of fathers and the heights of their adult sons is r = 0.52. This tells us that

taller than average fathers tend to have taller than average sons

The General Social Survey (GSS), conducted by the National Opinion Research Center at the University of Chicago, is a major source of data on social attitudes in the United States. Every other year, approximately 3,000 American adults aged 18 and over are interviewed in their homes all across the U.S. The subjects are asked their opinions about sex and marriage, about their attitudes toward women, welfare, foreign policy and many other issues. The sample for the GSS consists of

the 3,000 randomly chosen adults

For this histogram, which of the following is true: (left-skewed) (NEED PHOTO)

the mean is less than the median

You want to investigate the attitudes of students at your school toward the school's policy on extra fees for lab courses. You have a grant that will pay the costs of contacting about 500 students.

true

The correlation between the heights of fathers and the heights of their adult sons is r = 0.52. If the heights were first measured in feet (one foot equals 12 inches), and later measured in furlongs (one furlong equals 7,920 inches), the correlation between heights of fathers and heights of sons would be

unchanged: equal to 0.52.