Questions and Answers of Elementary Statistics In Social Research

You randomly select 25 newly constructed houses. The sample mean construction cost is $$181,000$ and the population standard deviation is $$28,000.$Assuming construction costs are normally
c = 0.99, x̅ = 24.7, s = 4.6, n = 50 Construct the indicated confidence interval for the population mean m using the t-distribution. Assume the population is normally distributed.
The monthly earnings (in Yens) of 32 randomly selected teachers in JapanUse the data set to(a) find the sample mean,(b) find the sample standard deviation, and(c) construct a 98% confidence interval
The annual earnings (in thousand Yens) of 40 randomly selected editors in JapanUse the data set to(a) find the sample mean,(b) find the sample standard deviation, and(c) construct a 98% confidence
In Exercise 31, the population mean salary is 305,046 Yen. Does the t-value fall between t0.98 and t0.98?Data from Exercises 31The monthly earnings (in Yens) of 32 randomly selected teachers in Japan
In Exercise 32, the population mean salary is 3,750 Yen. Does the t-value fall between -t0.98 and t0.98?Data from Exercises 32The annual earnings (in thousand Yens) of 40 randomly selected editors in
In a recent Indian Premier League season, the population standard deviation of the deliveries faced to score fifty runs for all batsmen was 6.37. The deliveries per fifty of 10 randomly selected
In Exercise 38, does it seem possible that the population mean could be within 10% of the sample mean? Explain.Data from Exercises 38In a recent Indian Premier League season, the population standard
In a survey of 1550 U.S. adults, 1054 said that they use the social media website Facebook. Find a point estimate for the population proportion of U.S. adults who use Facebook.
Use the data in Example 1 to construct a 95% confidence interval for the population proportion of U.S. adults who use Facebook.Data from Example 1In a survey of 1550 U.S. adults, 1054 said that they
The figure below is from a survey of 800 U.S. adults ages 18 to 29. Construct a 99% confidence interval for the population proportion of 18-to 29-year-olds who get their news on television. NEWS
You are running a political campaign and wish to estimate, with 95% confidence, the population proportion of registered voters who will vote for your candidate.Your estimate must be accurate within
A survey of adults in the United States found that 61% ate at a restaurant at least once in the past week. You randomly select 30 adults and ask them whether they ate at a restaurant at least once in
The table shows the distribution of household sizes in the United States for a recent year.Find the(a) mean,(b) variance,(c) standard deviation, and(d) expected value of the probability
The table shows the distribution of personal fouls per game for Garrett Temple in a recent NBA season.Find the(a) mean,(b) variance,(c) standard deviation, and(d) expected value of the probability
Use the probability distribution in Exercise 3 to find the probability of randomly selecting a game in which Garrett Temple had(a) fewer than four personal fouls,(b) at least three personal fouls,
From a pool of 16 candidates, 9 men and 7 women, the offices of president, vice president, secretary, and treasurer will be filled. (a) In how many different ways can the offices be filled? (b) What
To the left of z = 0.72 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the left of z = –3.08 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
To the right of z = –0.84 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Between z = 0 and z = 2.95 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Between z = -1.22 and 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 = 0.12 or to the right of z = 1.72 Find the indicated area under the standard normal curve. If convenient, use technology to find the area.
Twenty-eight percent of U.S. adults think that climate scientists understand the causes of climate change very well. You randomly select 25 U.S. adults.Find the probability that the number of U.S.
An auto parts seller finds that 1 in every 200 parts sold is defective. Use the geometric distribution to find the probability that (a) the first defective part is the fifth part sold, (b) the first
The table shows the results of a survey in which 3,405,100 public and 489,900 private school teachers were asked about their full-time teaching experience.(a) Find the probability that a randomly
The initial pressures for bicycle tires when first filled are normally distributed, with a mean of 70 pounds per square inch (psi) and a standard deviation of 1.2 psi.(a) Random samples of size 40
The life spans of car batteries are normally distributed, with a mean of 44 months and a standard deviation of 5 months.(a) Find the probability that the life span of a randomly selected battery is
A florist has 12 different flowers from which floral arrangements can be made. A centerpiece is made using four different flowers. (a) How many different centerpieces can be made? (b) What is the
Seventy percent of U.S. adults anticipate major cyberattacks on public infrastructure in the next five years. You randomly select 10 U.S. adults.(a) Construct a binomial distribution for the random
A researcher is collecting data about a college athletic conference and its student-athletes. A random sample of 40 student-athletes is selected and their numbers of hours spent on required athletic
Use the data in Example 1 and a 95% confidence level to find the margin of error for the mean number of hours spent on required athletic activities by all student-athletes in the conference. Assume
Use the data in Example 1 to construct a 95% confidence interval for the mean number of hours spent on required athletic activities by all student-athletes in the conference.Data from Example 1A
Use the data in Example 1 and technology to construct a 99% confidence interval for the mean number of hours spent on required athletic activities by all student-athletes in the conference.Data from
A college admissions director wishes to estimate the mean age of all students currently enrolled. In a random sample of 20 students, the mean age is found to be 22.9 years. From past studies, the
The researcher in Example 1 wants to estimate the mean number of hours spent on required athletic activities by all student-athletes in the conference.How many student-athletes must be included in
Find each probability using the standard normal distribution.(a) $P(z>-1.68)$(b) \(P(z
The random variable $x$ is normally distributed with the given parameters. Find each probability.(a) $\mu=9.2, \sigma \approx 1.62, P(x40.5)$(c) \(\mu=5.5, \sigma \approx 0.08, P(5.36
Find the probability that a randomly selected person has an IQ score higher than 125.Is this an unusual event? Explain.In a standardized IQ test, scores are normally distributed, with a mean score of
Find the probability that a randomly selected person has an IQ score between 95 and 105.Is this an unusual event? Explain.In a standardized IQ test, scores are normally distributed, with a mean score
What percent of the IQ scores are greater than 112 ?In a standardized IQ test, scores are normally distributed, with a mean score of 100 and a standardized deviation of 15.
Out of 2000 randomly selected people, about how many would you expect to have IQ scores less than 90 ?In a standardized IQ test, scores are normally distributed, with a mean score of 100 and a
What is the lowest score that would still place a person in the top $5 \%$ of the scores?In a standardized IQ test, scores are normally distributed, with a mean score of 100 and a standardized
What is the highest score that would still place a person in the bottom $10 \%$ of the scores?In a standardized IQ test, scores are normally distributed, with a mean score of 100 and a standardized
A random sample of 60 people is selected from this population. What is the probability that the mean IQ score of the sample is greater than 105 ? Interpret the result.In a standardized IQ test,
Are you more likely to randomly select one person with an IQ score greater than 105 or are you more likely to randomly select a sample of 15 people with a mean IQ score greater than 105? Explain.In a
Determine whether you can use a normal distribution to approximate the binomial distribution. If you can, find the mean and standard deviation. If you cannot, explain why.In a survey of U.S. adults,
Find the probability that the number of U.S. adults who say they have had someone take over their email accounts without their permission is (a) at most 40, (b) less than 45, and (c) exactly
1. Find the z-score that corresponds to a cumulative area of 0.3632.2. Find the z-score that has 10.75% of the distribution’s area to its right.
Find the z-score that corresponds to each percentile.1. P5 2. P50 3. P90
A veterinarian records the weights of cats treated at a clinic. The weights are normally distributed, with a mean of 9 pounds and a standard deviation of 2 pounds. Find the weight x corresponding to
Scores for the California Peace Officer Standards and Training test are normally distributed, with a mean of 50 and a standard deviation of 10. An agency will only hire applicants with scores in the
In a randomly selected sample of women ages 20 –34, the mean total cholesterol level is 179 milligrams per deciliter with a standard deviation of 38.9 milligrams per deciliter. Assume the total
0.8365 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 .09 .08 .07 .06 .05 .04
0.7357 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 .09 .08 .07 .06 .05 .04
0.063 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 .09 .08 .07 .06 .05 .04
0.3409 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 .09 .08 .07 .06 .05 .04
0.0284 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 .09 .08 .07 .06 .05 .04
0.81 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 .09 .08 .07 .06 .05 .04
0.8859 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 .09 .08 .07 .06 .05 .04
0.0156 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 .09 .08 .07 .06 .05 .04
P20 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 .09 .08 .07 .06 .05 .04 .03
P45 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 .09 .08 .07 .06 .05 .04 .03
P95 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 .09 .08 .07 .06 .05 .04 .03
P70 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 .09 .08 .07 .06 .05 .04 .03
P8 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 .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 Z 0 Z .09 .08 .07 .06 .05 .04 .03
P83 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 .09 .08 .07 .06 .05 .04 .03
P55 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 .09 .08 .07 .06 .05 .04 .03
Find the indicated z-score(s) shown in the graph. Area = 0.3520 z = ? 0 Z
.Find the indicated z-score(s) shown in the graph. Area = 0.5987 0 z = ? Z
Find the indicated z-score(s) shown in the graph. Area = 0.0233 0 z = ? Z
Find the indicated z-score(s) shown in the graph. z = ? 0 Area = 0.7190
Find the indicated z-score(s) shown in the graph. Area = 0.475 Area = 0.475 z = ? 0 z = ? Z
Find the indicated z-score(s) shown in the graph. Area = 0.05 Area = 0.05 z = ? 0 z=? Z
Find the z-score that has 15.6% of the distribution’s area to its right.Find the indicated z-score.
Find the z-score that has 88.9% of the distribution’s area to its right.Find the indicated z-score.
Find the z-score that has 43.5% of the distribution’s area to its left.Find the indicated z-score.
Find the z-score that has 31.5% of the distribution’s area to its left.Find the indicated z-score.
Find the z-score that has 4.887% of the distribution’s area to its right.Find the indicated z-score.
Find the z-score that has 93.1865% of the distribution’s area to its left.Find the indicated z-score.
Find the positive z-score for which 70% of the distribution’s area lies between -z and z.Find the indicated z-score.
Find the positive z-score for which 15% of the distribution’s area lies between -z and z.Find the indicated z-score.
In a survey of South African CEOs, the mean annual income was $$7.14$ million with a standard deviation of $$0.5$ million. What income represents the 90th percentile?(a) What income represents
The red blood cell counts (in grams per deciliter) for a population of adult females can be approximated by a normal distribution, with a mean of 13.5 grams per deciliter and a standard deviation of
The life span (in kilometers) for a population of a new brand of tires can be approximated by a normal distribution, with a mean of 80,000 kilometers and a standard deviation of 1,500 kilometers.(a)
The weights of bags of baby corns are normally distributed, with a mean of 500 grams and a standard deviation of 25 grams.Bags in the upper 2% are too heavy and must be repackaged. What is the most a
You sell a brand of thermostat that has a life expectancy that is normally distributed, with a mean life of 8.5 years and a standard deviation of 0.75 years. You want to give a guarantee for free
The number of times four people go grocery shopping in a month is given by the population values 51, 3, 5, 76. A probability histogram for the data is shown at the left. You randomly choose two of
A study analyzed the sleep habits of college students. The study found that the mean sleep time was 6.8 hours, with a standard deviation of 1.4 hours. Random samples of 100 sleep times are drawn from
Assume the training heart rates of all 20-year-old athletes are normally distributed, with a mean of 135 beats per minute and a standard deviation of 18 beats per minute, as shown in the figure.
The figure at the right shows the mean distances traveled by drivers each day. You randomly select 50 drivers ages 16 to 19. What is the probability that the mean distance traveled each day is
The mean room and board expense per year at four-year colleges is $$10,453$.You randomly select 9 four-year colleges. What is the probability that the mean room and board is less than $$10,750?$
Some college students use credit cards to pay for school-related expenses. For this population, the amount paid is normally distributed, with a mean of $$1615$ and a standard deviation of
μ = 225, σ = 40, n = 75 A population has a mean μ and a standard deviation σ. Find the mean and standard deviation of the sampling distribution of sample means with sample size n.
μ = 99, σ = 12, n = 225 A population has a mean μ and a standard deviation σ. Find the mean and standard deviation of the sampling distribution of sample means with sample size n.
μ = 1022, σ = 144, n = 360 A population has a mean μ and a standard deviation σ. Find the mean and standard deviation of the sampling distribution of sample means with sample size n.
μ = 4848, σ = 24, n = 1200 A population has a mean μ and a standard deviation σ. Find the mean and standard deviation of the sampling distribution of sample means with sample size n.
For a random sample of n = 49, find the probability of a sample mean being less than 37.2 when μ = 38 and σ = 2.17.The population mean and standard deviation are given. Find the indicated
For a random sample of n = 225, find the probability of a sample mean being greater than 37.2 when μ = 38 and σ = 2.17.The population mean and standard deviation are given. Find the indicated

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