Questions and Answers of Essentials Of Statistics

The efficiency of the rank correlation test is 0.91. What does that value tell us about the test?
True or false: If there is no linear correlation between systolic and diastolic blood pressure, then those two variables are not related in any way.
True or false: If the sample data lead us to the conclusion that there is sufficient evidence to support the claim of a linear correlation between systolic and diastolic blood pressure, then we could
If each systolic reading is exactly twice the diastolic reading, what is the value of the linear correlation coefficient r?
If you had computed the value of the linear correlation coefficient to be 3.335, what should you conclude?
If the sample data were to result in the scatterplot shown here, what is the value of the linear correlation coefficient r?
The table below lists days of the week selected by a random sample of 1005 subjects who were asked to identify the day of the week that is best for quality family time (based on results from a
Without performing actual calculations, examine the frequencies in the table given with Exercise 1. Do you expect the value of the X2 test statistic to be large or small? Do you expect the P-value to
Goodness-of-Fit Test For the goodness-of-fit test described in Exercise 1, identify the number of degrees of freedom and the critical value of X2, assuming a 0.05 significance level.Exercise 1The
Is the hypothesis test left-tailed, right-tailed, or two-tailed?The table lists frequencies for randomly selected nonfatal occupation injuries arranged according to day of the week. Assume that we
Given that the P-value for the hypothesis test is 0.971, what do you conclude?The table lists frequencies for randomly selected nonfatal occupation injuries arranged according to day of the week.
Is the hypothesis test left-tailed, right-tailed, or two-tailed?Randomly selected subjects were asked about the use of marijuana for medical purposes. Assume that we want to use a 0.05 significance
Find the number of degrees of freedom and the critical value.Randomly selected subjects were asked about the use of marijuana for medical purposes. Assume that we want to use a 0.05 significance
Given that the P-value for the hypothesis test is 0.836, what do you conclude?Randomly selected subjects were asked about the use of marijuana for medical purposes. Assume that we want to use a 0.05
The following histogram is obtained from the daily rainfall amounts (in.) in Boston for a year. If we want to conduct a hypothesis test of a claim about the mean, there is a requirement that the
For the methods of this section, which of the following statements are true?a. The requirement of a simple random sample is satisfied if we have matched pairs of voluntary response data.b. If we have
Identify the null and alternative hypotheses resulting from the claim that the proportion of women who agree with the given statement is equal to the proportion of men who agree.Randomly selected
When testing the claim that p1 = p2, a test statistic of z = 2.04 is obtained. Find the P-value obtained from this test statistic.Randomly selected subjects were asked if they agreed with the
Listed below are the costs (in dollars) of repairing the front ends and rear ends of different cars when they were damaged in controlled low-speed crash tests (based on data from the Insurance
Determine whether the following statement is true or false: When testing a claim about the means of two independent populations, the alternative hypothesis can never contain the condition of equality.
Determine whether the following statement is true or false: When testing the claim that the mean annual income of statistics professors in New York is equal to the mean annual income of statistics
Determine whether the following statement is true or false: When using the methods of this chapter to test a claim that two population proportions are equal, each of the two samples must satisfy the
The USA Today Web site posted this question: “Have you considered getting a home generator for backup power?” Among 928 Internet users who chose to respond, 41% answered “yes.” If we use
Students of the author collected a simple random sample of times (sec) of wristwatch errors, and a few of those times are listed below. Negative values correspond to watches that are running ahead of
Refer to the hypothesis test described in Exercise 1.a. Is the hypothesis test left-tailed, right-tailed, or two-tailed?b. If the requirements are satisfied, what distribution should be used for the
If we use technology to conduct the hypothesis test described in Exercise 1, we get a P-value of 0.1150.a. What should we conclude about the null hypothesis?b. What is the final conclusion that
In a recent Gallup poll of 511 adults, 64% said that they were in favor of the death penalty for a person convicted of murder. We want to use a 0.01 significance level to test the claim that the
Find the P-value in a test of the claim that the mean IQ score of acupuncturists is equal to 100, given that the test statistic is z = -2.00.
The claim is that for the nicotine amounts in king-size cigarettes, μ > 1.10 mg. The sample size is n = 25 and the test statistic is t = 3.349. Either use technology to find the P-value or use
The claim is that for the tar amounts in king-size cigarettes, μ > 20.0 mg. The sample size is n = 25 and the test statistic is t = 1.733.Either use technology to find the P-value or use Table
The claim is that for measurements of standard head injury criteria in car crash tests, μ = 475 HIC (standard head injury condition units). The sample size is n = 21 and the test statistic is t =
Six human skulls from around 4000 b.c. were measured, and the lengths have a mean of 94.2 mm and a standard deviation of 4.9 mm. If you want to construct a 95% confidence interval estimate of the
Refer to Exercise 7 and assume that the requirements are satisfied. Find the critical values that would be used to construct a 95% confidence interval estimate of σ.Exercise 7Six human skulls from
The test statistic of z = 2.00 is obtained when testing the claim that p > 0.5.Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values.
The test statistic of z = -2.00 is obtained when testing the claim that p Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values. P-value =
With H1: p ≠ 2/3, the test statistic is z = 2.50.Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values. P-value = area to the left of the
With H1: p Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values. P-value = area to the left of the test statistic Left-tailed Left Start
With H1: p > 7/8, the test statistic is z = 2.88.Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values. P-value = area to the left of
We can test a claim about a population proportion using the P-value method of hypothesis testing or the critical value method of hypothesis testing, or we could base our conclusion on a confidence
Confidence level is 95%, σ is known to be $4,385,000, and the dotplot of a sample of Red Sox baseball player salaries is as shown below.Assume that we want to construct a confidence interval. Do one
Confidence level is 90%, σ is not known, and the dotplot of IQ scores of 20 randomly selected statistics instructors is as shown below.Assume that we want to construct a confidence interval. Do one
Confidence level is 99%, σ is not known, and the dotplot of a sample of 40 values of professional baseball player salaries is as shown below.Assume that we want to construct a confidence interval.
Confidence level is 99%, σ is known to be $4,385,000, and the dotplot of 40 sample values of professional baseball players is as shown in Exercise 7.Assume that we want to construct a confidence
Find the indicated critical value.z0.025
Find the indicated critical value.z0.01
Find the indicated critical value.z0.05
Find the indicated critical value.z0.03
Find the probability of an IQ less than 85.
Mensa International calls itself “the international high IQ society,” and it has more than 100,000 members. Mensa states that “candidates for membership of Mensa must achieve a score at or
Find P80, the 80th percentile for the red blood cell counts of women.
If 25 women are randomly selected, find the probability that the mean of their red blood cell counts is less than 4.444.Assume that red blood cell counts of women are normally distributed with a mean
What percentage of women have red blood cell counts in the normal range from 4.2 to 5.4?Assume that red blood cell counts of women are normally distributed with a mean of 4.577 and a standard
An Office Team survey of 150 executives found that 93.3% of them said that they would be concerned about gaps in a résumé of a job applicant. Based on these results, such randomly selected groups
A new integrated circuit board is being developed for use in computers. In the early stages of development, a lack of quality control results in a 0.2 probability that a manufactured integrated
If boys and girls are equally likely, groups of 400 births have a mean of 200 girls and a standard deviation of 10 girls. Is 232 girls in 400 births an unusually high number of girls?
If boys and girls are equally likely, groups of 400 births have a mean of 200 girls and a standard deviation of 10 girls. Is 185 girls in 400 births an unusually low number of girls?
If six people are randomly selected, find the probability that none of them has brown eyes.Assume that 40% of the population has brown eyes based on data from Dr. P. Sorita at Indiana University.
Find the probability that among six randomly selected people, exactly four of them have brown eyes.Assume that 40% of the population has brown eyes based on data from Dr. P. Sorita at Indiana
In the month preceding the creation of this exercise, the author made no phone calls on 19 of the 30 days in the month. Assume that 10 days from that month are randomly selected with replacement.
A denote the event of placing a $1 straight bet on the Florida Play 4 lottery and winning. The chance of event A occurring is 1 in 10,000. What is the value of P(A)? What is the value of P(A)?
Given that the following statement is incorrect, rewrite it correctly: “The probability of a baby being born a boy is 50–50.”
Which of the following values are not probabilities?5:2 3/7 7/3 -0.9 0.123 123/456 456/123 0 1
“Who was the 14th president of the United States: Taylor, Fillmore, Pierce, or Buchanan?” If you make a random guess for the answer to that question, what is the probability that your answer is
“Which of the following is the mean of the first 100 digits of pi after the decimal point: 4.4, 4.5, 4.6, 4.7, or 4.8?” If you make a random guess for the answer to that question, what is the
When rolling a single die, what is the probability that the outcome is 7?
Exactly 205 girls.Assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that
Exactly 380 girls.Assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that
Exactly 111 girls.Assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that
Assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that the result is far
When arriving at the traffic light closest to the author’s home, there is a 25% chance that the light will be red.Express the indicated degree of likelihood as a probability value between 0 and 1.
While this exercise was being created, Weather.com indicated that there is a 20% chance of rain for the author’s home region.Express the indicated degree of likelihood as a probability value
Based on a Harris poll, there is a 50−50 chance that a randomly selected adult has pierced ears.Express the indicated degree of likelihood as a probability value between 0 and 1.
When guessing the answer to a multiple-choice question on an SAT test, the chance of guessing correctly is 1 in 5.Express the indicated degree of likelihood as a probability value between 0 and 1.
When rolling a pair of dice at the Bellagio Casino in Las Vegas, there is 1 chance in 36 that the outcome is a 12.Express the indicated degree of likelihood as a probability value between 0 and 1.
It is impossible to pass a statistics test without studying.Express the indicated degree of likelihood as a probability value between 0 and 1.
Find the probability of selecting someone who uses drugs. Is the result close to the probability of 0.134 for a positive test result?Refer to the sample data in Table 4-1, which is included with the
Find the probability of selecting someone who does not use drugs. Is the result close to the probability of 0.866 for a negative test result?Refer to the sample data in Table 4-1, which is included
In a recent year, 304 of the approximately 300,000,000 people in the United States were struck by lightning. Estimate the probability that a randomly selected person in the United States will be
What is wrong with the expression P(A) + P(A̅) = 0.5?
A gambler plans to play the casino dice game called craps, and he plans to place a bet on the “pass line.” Let A be the event of winning. Based on the rules used in almost all casinos, P(A) =
One form of the rule of complements is this: P(A or A̅) = 1.Write a sentence describing the message that this rule represents.
Asking for a date through a Twitter post.Asking for a date in French, the romance language.Determining Whether Events Are Disjoint. Determine whether the two events are disjoint for a single trial.
Randomly selecting a survey respondent and getting someone who believes in UFOs.Randomly selecting a survey respondent and getting someone who believes in the devil.Determining Whether Events Are
Randomly selecting a statistics student and getting one who uses a TI calculator in class.Randomly selecting a statistics student and getting one who uses the STATDISK computer program.Determining
Randomly selecting a drug screening result and getting one that is a false negative.Randomly selecting a drug screening result and getting one from someone who is not a drug user.Determining Whether
Randomly selecting a drug screening result and getting one that is a false positive.Randomly selecting a drug screening result and getting one from someone who uses drugs.Determining Whether Events
Randomly selecting a drug screening result and getting one that is a false positive.Randomly selecting a drug screening result and getting one from someone who does not use drugs.Determining Whether
Randomly selecting a drug screening result and getting one that is a false positive.Randomly selecting a drug screening result and getting one that is a false negative.Determining Whether Events Are
A Marist poll survey showed that 47% of respondents chose “whatever” as the most annoying phrase used in conversation. What is the probability of randomly selecting someone choosing something
According to the National Association for College Admissions Counseling and USA Today, 19.8% of college students take at least one class online.What is the probability of randomly selecting a college
If one of the physicians is randomly selected, find the probability of getting one who made a correct dosage calculation or was given the bottle with a concentration label.Dosage Calculations. Use
Let R be the event of randomly selecting a senator and getting a Republican, and let D represent the event of randomly selecting a second different senator and getting a Democrat. Use words to
A: When a month is randomly selected and ripped from a calendar and destroyed, it is July.B: When a different month is randomly selected and ripped from a calendar, it is November.Independent and
A: When a baby is born, it is a girl.B: When a second baby is born into a different family, it is also a girl.Independent and Dependent Events.(a) determine whether events A and B are independent or
A: When a baby is born, it is a girl.B: When a single die is rolled, the outcome is 6.Independent and Dependent Events.(a) determine whether events A and B are independent or dependent, (b) find P(A
A: When a day of the week is randomly selected, it is a Saturday.B: When a second different day of the week is randomly selected, it is a Monday.Independent and Dependent Events.(a) determine whether
A: When one of the 222 coins listed in Data Set 21 is randomly selected, it is one of the 5 Indian pennies.B: When another one of the 222 coins listed in Data Set 21 is randomly selected, it is also
A: When the first digit (0 through 9) of a four-digit lottery number is chosen by someone buying a ticket, it is the same first digit that is later drawn in the official lottery.B: When the second
A: When a survey subject is randomly selected from the 100 senators in the 111th Congress, it is one of the 58 Democrats.B: When a second different senator is randomly selected, it is the one senator
A: When an M&M is randomly selected from the 100 M&Ms listed in Data Set 20, it is one of the 8 yellow M&Ms.B: When a second different M&M is randomly selected from those listed in Data Set 20, it is

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