Questions and Answers of Elementary Statistics In Social Research

For a random sample of n = 60, find the probability of a sample mean being greater than 132 when μ = 130 and σ = 16.1.The population mean and standard deviation are given. Find the indicated
For a random sample of n = 25, find the probability of a sample mean being less than 100 or greater than 102 when μ = 100 and σ = 4.5.The population mean and standard deviation are given. Find the
Repeat Exercise 20 for samples of size 18 and 12.What happens to the mean and the standard deviation of the distribution of sample means as the sample size decreases?Data from Exercises 20The scores
A machine is set to fill paint cans with a mean of 5 kilograms and a standard deviation of 0.02 kilograms. A random sample of 75 cans has a mean of 4.99 kilograms. The machine needs to be reset when
Chocolate Cookies A machine is set to pack chocolate cookies with a mean of 125 grams and a standard deviation of 4 grams. A random sample of 16 packs has a mean of 125.5 grams. The machine needs to
Cloth Cutter The lengths of cloth a machine cuts for making dresses are normally distributed, with a mean of 3 meters and a standard deviation of 0.25 meters.(a) What is the probability that a
Muffins The weights of muffin cartons are normally distributed with a mean weight of 1.25 kilograms and a standard deviation of 0.1 kilograms.(a) What is the probability that a randomly selected
Two binomial experiments are listed. Determine whether you can use a normal distribution to approximate the distribution of x, the number of people who reply yes. If you can, find the mean and
Use a continuity correction to convert each binomial probability to a normal distribution probability.1. The probability of getting between 270 and 310 successes, inclusive 2. The probability of
In a survey of 8-to 18-year-old heavy media users in the United States, 47% said they get fair or poor grades (C and below). You randomly select forty-five 8- to 18-year-old heavy media users in the
A study on aggressive driving found that 47% of drivers say they have yelled at another driver. You randomly select 200 drivers in the United States and ask them whether they have yelled at another
A study of National Football League (NFL) retirees, ages 50 and older, found that 62.4% have arthritis. You randomly select 75 NFL retirees who are at least 50 years old and ask them whether they
A survey of cross-border money transfers found that in 38% cases, the beneficiary account has suffered double charging, in contradiction to European Union rules. You randomly select 200 crossborder
A survey of German adults found that 73% of customers who shop online pay through PayPal. You randomly select 150 German adults who shop online. Find the probability that the number who pay through
To the left of z = 0.35 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the right of z = –0.46 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = –1.625 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the right of z = 2.62 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = –0.11 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Between z = –1.96 and z = 0 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Between z = –1.55 and z = 1.04 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Between z = 0.15 and z = 1.64 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = –1.62 and to the right of z = 1.62 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
P(z < 1.36)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(–1.12 < z < 1.75)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(z < –1.50 or z > 1.50)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(x < 82)The random variable x is normally distributed with mean μ = 74 and standard deviation σ = 8. Find the indicated probability.
P(x > 68.4)The random variable x is normally distributed with mean μ = 74 and standard deviation σ = 8.Find the indicated probability.
P(x > 70)The random variable x is normally distributed with mean μ = 74 and standard deviation σ = 8. Find the indicated probability.
P(x < 57)The random variable x is normally distributed with mean μ = 74 and standard deviation σ = 8. Find the indicated probability.
P(58 < x < 66)The random variable x is normally distributed with mean μ = 74 and standard deviation σ = 8.Find the indicated probability.
0.1 Use the Standard Normal Table or technology to find the z-score that corresponds to the cumulative area or percentile. Table 4-Standard Normal Distribution Arca 0 z Z .09 .08 .07 .06 .05 .04 .03
0.993 Use the Standard Normal Table or technology to find the z-score that corresponds to the cumulative area or percentile. Table 4-Standard Normal Distribution Arca z 0 z Z .09 .08 .07 .06 .05 .04
P2 Use the Standard Normal Table or technology to find the z-score that corresponds to the cumulative area or percentile. Table 4-Standard Normal Distribution Arca 0 z Z .09 .08 .07 .06 .05 .04 .03
P67 Use the Standard Normal Table or technology to find the z-score that corresponds to the cumulative area or percentile. Table 4-Standard Normal Distribution Arca 0 z Z .09 .08 .07 .06 .05 .04 .03
P46 Use the Standard Normal Table or technology to find the z-score that corresponds to the cumulative area or percentile. Table 4-Standard Normal Distribution Arca 0 z Z .09 .08 .07 .06 .05 .04 .03
P(x ≥ 28)Write the binomial probability in words. Then, use a continuity correction to convert the binomial probability to a normal distribution probability.
P(x > 18)Write the binomial probability in words. Then, use a continuity correction to convert the binomial probability to a normal distribution probability.
P(x ≤ 32)Write the binomial probability in words. Then, use a continuity correction to convert the binomial probability to a normal distribution probability.
P(x < 50)Write the binomial probability in words. Then, use a continuity correction to convert the binomial probability to a normal distribution probability.
P(54 < x < 64)Write the binomial probability in words. Then, use a continuity correction to convert the binomial probability to a normal distribution probability.
Determine whether the random variable x is discrete or continuous. Explain your reasoning.(a) Let x represent the number of lightning strikes that occur in Wyoming during the month of June.(b) Let x
The table lists the number of wireless devices per household in a small town in the United States.(a) Construct a probability distribution.(b) Graph the probability distribution using a histogram and
Thirty-six percent of U.S. adults have postponed medical checkups or procedures to save money. You randomly select nine U.S. adults. Find the probability that the number of U.S. adults who have
The five-year success rate of kidney transplant surgery from living donors is 86%. The surgery is performed on six patients.(a) Construct a binomial distribution.(b) Graph the binomial distribution
An online magazine finds that the mean number of typographical errors per page is five. Find the probability that the number of typographical errors found on any given page is (a) exactly five, (b)
Basketball player Dwight Howard makes a free throw shot about 56% of the time. Find the probability that(a) the first free throw shot he makes is the fourth shot,(b) the first free throw shot he
Which event(s) in Exercise 6 can be considered unusual? Explain your reasoning.Data from Exercises 6Basketball player Dwight Howard makes a free throw shot about 56% of the time. Find the probability
1. Which normal curve has a greater mean?2. Which normal curve has a greater standard deviation?
The scaled test scores for the New York State Grade 4 Common Core Mathematics Test are normally distributed. The normal curve shown below represents this distribution. What is the mean test score?
1. Find the cumulative area that corresponds to a z-score of 1.15.2. Find the cumulative area that corresponds to a z-score of –0.24.
Find the area under the standard normal curve to the left of z = –0.99.
Find the area under the standard normal curve to the right of z = 1.06.
Find the area under the standard normal curve between z = –1.5 and z = 1.25.
To the left of z = 0.26 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = –2.87 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = –1.865 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = 1.185 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the right of z = –0.99Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the right of z = 2.65Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the right of z = –0.955 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the right of z = 1.175Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Between z = –2.48 and z = 0 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Between z = –2.25 and z = 2.25 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Between z = –1.96 and z = 1.96 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = –0.15 and to the right of z = 0.15 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = –2.56 and to the right of z = 1.25 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
You work for a consumer watchdog publication and are testing the advertising claims of a flash drive. The manufacturer claims that the life spans of the flash drives are normally distributed, with a
You are performing a study about monthly per capita cocoa consumption in a city. A previous study found monthly per capita cocoa consumption to be normally distributed, with a mean of 21 grams and a
The test scores for the girls who received their Australian Tertiary Admission Rank (ATAR) are normally distributed. In a recent year, the mean test score for the girls was 66.25 and the standard
The test scores for the boys who received their Australian Tertiary Admission Rank (ATAR) are normally distributed. In a recent year, the mean test score for the boys was 63.75 and the standard
P(z < 2.32)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(z < –0.26)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(z > 3.285)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(z > –2.55)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(–1.35 z < 0)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(0 < z < 2.315)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(-2.46 < z < 3.1)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(–0.18 < z < 2.46)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(z < -3.1 or z > 3.1)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
P(z < –2.46 or z > 2.46)Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability.
A national study found that college students with jobs worked an average of 22 hours per week. The standard deviation is 9 hours. A college student with a job is selected at random. Find the
A survey indicates that for each trip to a supermarket, a shopper spends an average of 43 minutes with a standard deviation of 12 minutes in the store. The lengths of time spent in the store are
Triglycerides are a type of fat in the bloodstream. The mean triglyceride level for U.S. adults (ages 20 and older) is 97 milligrams per deciliter. Assume the triglyceride levels of U.S. adults who
P(x < 180)The random variable x is normally distributed with mean μ = 174 and standard deviation σ = 20.Find the indicated probability.
P(x < 160)The random variable x is normally distributed with mean μ = 174 and standard deviation σ = 20.Find the indicated probability.
P(x > 185)The random variable x is normally distributed with mean μ = 174 and standard deviation σ = 20.Find the indicated probability.
P(x > 170)The random variable x is normally distributed with mean μ = 174 and standard deviation σ = 20.Find the indicated probability.
P(170 < x < 195)The random variable x is normally distributed with mean μ = 174 and standard deviation σ = 20.Find the indicated probability.
P(155 < x < 172)The random variable x is normally distributed with mean μ = 174 and standard deviation σ = 20.Find the indicated probability.
In a survey of South African CEOs, the annual incomes were normally distributed, with a mean of $$7.14$ million and a standard deviation of $$0.5$ million. Find the probability that a randomly
The ages of prime ministers of Sri Lanka, when they were first sworn to office, are normally distributed with a mean of 58.21 years and a standard deviation of 11.56 years. Find the probability that
The monthly maintenance charges of an organization are normally distributed, with a mean of $$500$ and a standard deviation of$$150.$ Find the probability that a randomly selected utility bill
The amounts of time per workout a person uses an elliptical cross trainer are normally distributed, with a mean of 10 minutes and a standard deviation of 2 minutes. Find the probability that a
Use the normal distribution in Exercise 13.(a) What percent of the SAT total scores are less than 1200?(b) Out of 500 randomly selected SAT total scores, about how many would you expect to be greater
ACT Composite Scores Use the normal distribution in Exercise 14.(a) What percent of the ACT composite scores are less than 16?(b) Out of 1000 randomly selected ACT composite scores, about how many
Pregnancy Length Use the normal distribution in Exercise 15.(a) What percent of the new mothers had a pregnancy length of less than 280 days?(b) What percent of the new mothers had a pregnancy length
Red Blood Cell Count Use the normal distribution in Exercise 16.(a) What percent of the adult males have a red blood cell count less than 5.75 million cells per microliter?(b) What percent of the
The probability that you will clear an entrance exam in any attempt is 0.26. Find the probability that you(a) clear the exam on the fourth attempt,(b) clear the exam on the first, second or third
A spare parts seller finds that 3 in every 100 parts sold is defective. Find the probability that(a) the first defective part is the eighth part sold,(b) the first defective part is the first, second

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