Starts exam 2 extra credit
Observational..
A car wash operator wants to identify his average annual profits.
#45
A certain test preparation course is designed to help students improve their scores on the MCAT exam. A mock exam is given at the beginning and end of the course to determine the effectiveness of the course. The following measurements are the net change in 3 students' scores on the exam after completing the course: 1,6,5 Using these data, construct a 98% confidence interval for the average net change in a student's score after completing the course. Assume the population is approximately normal. Step 1 of 4: Calculate the sample mean for the given sample data. Round your answer to one decimal place. 2) Calculate the sample standard deviation for the given sample data. Round your answer to one decimal place. 3) Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places. 4) Construct the 98% confidence interval. Round your answer to one decimal place.
mean
A company has given you the task to research the amount of snowfall in Cleveland from December to February. Would you be more interested in looking at the mean, median, or mode?
Qualit, neither, ordinal
A company is evaluating customer satisfaction with one of their products. A survey of 400 persons is conducted. Each person is asked: "What is your level of satisfaction with the company's products?" 1) Poor 2) Average 3) Good 4) Excellent
Experimental
A deli cart entrepreneur wants to study if reducing prices on Tuesdays will increase profits. A car wash operator wants to know if closing the store early on weeknights will hurt profits.
#70 Observational
A general manager of a restaurant wants to study the average age of his clientele.
Experimt
A gift shop owner wants to study if providing a discount for local residents will generate additional revenue.
#82
A quality-conscious disk manufacturer wishes to know the fraction of disks his company makes which are defective. Step 1 of 2: Suppose a sample of 433 floppy disks is drawn. Of these disks, 369 were not defective. Using the data, estimate the proportion of disks which are defective. Enter your answer as a fraction or a decimal number rounded to three decimal places.
#87
A racing car consumes a mean of 101 gallons of gas per race with a variance of 49. If 43 racing cars are randomly selected, what is the probability that the sample mean would differ from the population mean by greater than 2.4 gallons? Round your answer to four decimal places.
#22
A random sample of 6 fields of corn has a mean yield of 23.8 bushels per acre and standard deviation of 4.46 bushels per acre. Determine the 95% confidence interval for the true mean yield. Assume the population is approximately normal. Step 1 of 2: Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places. Step 2 of 2: Construct the 95% confidence interval. Round your answer to one decimal place.
#86
A soft drink machine outputs a mean of 22 ounces per cup. The machine's output is normally distributed with a standard deviation of 4 ounces. What is the probability of putting less than 29 ounces in a cup? Round your answer to four decimal places.
#44
A town recently dismissed 7 employees in order to meet their new budget reductions. The town had 8 employees over 50 years of age and 16 under 50. If the dismissed employees were selected at random, what is the probability that exactly 2 employees were over 50? Express your answer as a fraction or a decimal number rounded to four decimal places.
#55
An economist wants to estimate the mean per capita income (in thousands of dollars) for a major city in Texas. He believes that the mean income is $24.6, and the standard deviation is known to be $7.9. How large of a sample would be required in order to estimate the mean per capita income at the 80% level of confidence with an error of at most $0.56? Round your answer up to the next integer.
#56
Assume the random variable X has a binomial distribution with the given probability of obtaining a success. Find the following probability, given the number of trials and the probability of obtaining a success. Round your answer to four decimal places. P(X=11), n=19, p=0.7
#88
Calculate the standard score of the given X value, X=52, where μ=46.6 and σ=41.9 and indicate on the curve where z will be located. Round the standard score to two decimal places.
Outcome
Each individual result of a probability experiment is called a(n)
Confounding variables
Factors that influence the results of a study that the researcher did not, or could not, account for are known as .
#84
Find the area under the standard normal curve between z=0.04 and z=2.64. Round your answer to four decimal places, if necessary.
#37
Find the area under the standard normal curve to the left of z=−0.95
#85
Find the area under the standard normal curve to the left of z=−2.75 and to the right of z=2.62. Round your answer to four decimal places, if necessary.
#43
Find the area under the standard normal curve to the right of z=−2.34. Round your answer to four decimal places, if necessary.
The margin of error will increase because the critical value will increase and the sample size, n, is located in the denominator of the formula for margin of error. The increased margin of error will cause the confidence interval to be wider.
If the sample size is decreased while the level of confidence remains the same, how will the width of a confidence interval for population mean be affected? Assume that the population standard deviation is unknown and the population distribution is approximately normal.
#80
If you throw exactly one head in three tosses of a coin you win $67. If not, you pay me $36 Step 1 of 2: Find the expected value of the proposition. Round your answer to two decimal places. Losses must be expressed as negative values. Step 2 of 2: If you played this game 872 times how much would you expect to win or lose? Round your answer to two decimal places.
#13
Suppose that diastolic blood pressure readings of adult males have a bell-shaped distribution with a mean of 79 mmHg and a standard deviation of 10 mmHg. Using the empirical rule, what percentage of adult males have diastolic blood pressure readings that are less than 89 mmHg? Please do not round your answer.
#75
Suppose that grade point averages of undergraduate students at one university have a bell-shaped distribution with a mean of 2.53 and a standard deviation of 0.41. Using the empirical rule, what percentage of the students have grade point averages that are greater than 1.3? Please do not round your answer.
#40
The FBI wants to determine the effectiveness of their 10 Most Wanted list. To do so, they need to find out the fraction of people who appear on the list that are actually caught. In an earlier study, the population proportion was estimated to be 0.3. How large a sample would be required in order to estimate the fraction of people who are captured after appearing on the 10 Most Wanted list at the 85% confidence level with an error of at most 0.03?
#33. Quantitative, contin, ratio
The amount of time each of five randomly selected basketball players play during a game
Quantitativ, discrete, ratio?
The heart beats per minute of 40 randomly selected people The prices of 50 randomly selected cars
#66
The mean life of a television set is 123 months with a standard deviation of 19 months. If a sample of 55 televisions is randomly selected, what is the probability that the sample mean would be greater than 121.8 months? Round your answer to four decimal places.
#64
The mean life of a television set is 123 months with a standard deviation of 19 months.If a sample of 55 televisions is randomly selected, what is the probability that the sample mean would be greater than 121.8 months? Round your answer to four decimal places.
#6
The operation manager at a tire manufacturing company believes that the mean mileage of a tire is 25,835 miles, with a variance of 18,207,290. What is the probability that the sample mean would differ from the population mean by less than 104 miles in a sample of 89 tires if the manager is correct? Round your answer to four decimal places.
#69
The random variable X is a binomial random variable with n=13 and p=0.8. What is the expected value of X? Do not round your answer.
#71
The random variable X is a binomial random variable with n=17 and p=0.2. What is the standard deviation of X? Round your answer to two decimal places.
Sample Space
The set of all possible outcomes for a given probability experiment is called the
#26
The time spent waiting in the line is approximately normally distributed. The mean waiting time is 4 minutes and the variance of the waiting time is 1. Find the probability that a person will wait for more than 5 minutes. Round your answer to four decimal places.
#83
The time spent waiting in the line is approximately normally distributed. The mean waiting time is 5 minutes and the standard deviation of the waiting time is 2 minutes. Find the probability that a person will wait for between 2 and 6 minutes. Round your answer to four decimal places.
#30
There are 7 black balls and 8 red balls in an urn. If 4 balls are drawn without replacement, what is the probability that more than 1 black ball is drawn? Express your answer as a fraction or a decimal number rounded to four decimal places.
#53
Unknown to a medical researcher, 9 out of 17 patients have a heart problem that will result in death if they receive the test drug. 5 patients are randomly selected to receive the drug and the rest receive a placebo. What is the probability that at least 4 patients will die? Express your answer as a fraction or a decimal number rounded to four decimal places.
#72
You are going to play mini golf. A ball machine that contains 22 green golf balls, 18 red golf balls, 24 blue golf balls, and 25 yellow golf balls, randomly gives you your ball. What is the probability that you end up with a green golf ball? Express your answer as a simplified fraction or a decimal rounded to four decimal places.
