Expert answer:Need statistics Assistance for an exam about proba

Answer & Explanation:need assistance with questions that  I have already done. just need to know if they are correct.statistics_analysis__exam_08_1an__1_.docx
statistics_analysis__exam_08_1an__1_.docx

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1.
If a fan purchased a bag with 30 peanuts, what is the lowest level at which this would be a significant
event?
A. 0.05
B. 0.025
C. 0.01
D. It is not significant at any of the levels given
ANSWER B
2. A poll of 1,068 adult Americans reveals that 52% of the voters surveyed prefer the Democratic candidate for
the presidency. At the 0.05 significance level, test the claim that more than half of all voters prefer the
Democrat.
A. Reject the null hypothesis. Conclude that there is insufficient evidence that more than half
of all voters prefer Democrats.
B. Do not reject the null hypothesis. Conclude that there is sufficient evidence that more than
half of all voters prefer Democrats.
C. Reject the null hypothesis. Conclude that there is sufficient evidence that more than half of
all voters prefer Democrats.
D. Do not reject the null hypothesis. Conclude that there is insufficient evidence that more
than half of all voters prefer Democrats.
ANSWER D
3.
A.
is less than 1 standard deviation above the claimed mean.
B.
is more than 4 standard deviations above the claimed mean.
C.
is less than 1 standard deviation above the claimed mean.
D.
is more than 4 standard deviations above the claimed mean.
ANSWER D
4. In the past, the mean running time for a certain type of flashlight battery has been 8.0 hours. The
manufacturer has introduced a change in the production method and wants to perform a hypothesis test to
determine whether the mean running time has increased as a result. The hypotheses are:
H0 : µ = 8.0 hours
Ha : µ > 8.0 hours
Explain the meaning of a Type II error.
A. Concluding that µ > 8.0 hours when in fact µ > 8.0 hours
B. Failing to reject the hypothesis that µ = 8.0 hours when in fact µ >
8.0 hours
C. Concluding that µ > 8.0 hours
D. Failing to reject the hypothesis that µ = 8.0 hours when in fact µ = 8.0 hours
ANSWER B
5. A study of a brand of “in the shell peanuts” gives the following results:
A significant event at the 0.01 level is a fan getting a bag with how many peanuts?
A. 30 peanuts
B. 25 or 30 peanuts
C. 25 or 55 peanuts
D. 25 peanuts
ANSWER D
6. A psychologist claims that more than 29 percent of the professional population suffers from problems due to
extreme shyness. Assuming that a hypothesis test of the claim has been conducted and that the conclusion is
failure to reject the null hypothesis, state the conclusion in non-technical terms.
A. There is sufficient evidence to support the claim that the true proportion is less than 29
percent.
B. There is not sufficient evidence to support the claim that the true proportion is greater than
29 percent.
C. There is sufficient evidence to support the claim that the true proportion is equal to 29
percent.
D. There is sufficient evidence to support the claim that the true proportion is greater than 29
percent.
ANSWER B
7. A consumer group claims that the mean running time for a certain type of flashlight battery is not the same
as the manufacturer’s claims. Determine the null and alternative hypotheses for the test described.
A.
H0: µ = Manufacturer’s claims
Ha: µ < Manufacturer’s claims B. H0: µ = Manufacturer’s claims Ha: µ  Manufacturer’s claims C. H0: µ = Manufacturer’s claims Ha: µ > Manufacturer’s claims
D.
H0: µ  Manufacturer’s claims
Ha: µ = Manufacturer’s claims
ANSWER B
8. The principal of a middle school claims that annual incomes of the families of the seventh-graders at his
school vary more than the annual incomes of the families of the seventh-graders at a neighboring school,
which have variation described by = $13,700. Assume that a hypothesis test of the claim has been
conducted and that the conclusion of the test was to reject the null hypothesis. Identify the population to which
the results of the test apply.
A. The current seventh graders at the principal’s school
B. Seventh graders’ families at the school with a standard deviation of $13,700
C. All of the families of the class of seventh graders at the principal’s school
D. All seventh graders’ families
ANSWER C
9.
A researcher wants to check the claim that convicted burglars spend an average of 18.7 months in jail. She
takes a random sample of 35 such cases from court files and finds that
months. Assume that the
population standard deviation is 7 months. Test the null hypothesis that µ = 18.7 at the 0.05 significance level.
A.
Do not reject the null hypothesis and conclude that the claim that the mean is different from 18.7
months is supported.
B.
Do not reject the null hypothesis and conclude that the claim that the mean is different from 18.7
months cannot be supported.
C.
Reject the null hypothesis and conclude that the claim that the mean is different from 18.7
months is supported.
D.
Reject the null hypothesis and conclude that the claim that the mean is different from 18.7
months cannot be supported.
ANSWER B
10. The owner of a football team claims that the average attendance at home games is over 4000, and he is
therefore justified in moving the team to a city with a larger stadium. Assume that a hypothesis test of the claim
has been conducted and that the conclusion of the test was to reject the null hypothesis. Identify the population
to which the results of the test apply.
A. All games played by the team in question in which the attendance is over 4000
B. All future home games to be played by the team in question
C. All home games played by the team in question
D. None of the populations given are appropriate
ANSWER A
11. A psychologist claims that more than 19 percent of the population suffers from professional problems due
to extreme shyness. Assume that a hypothesis test of the claim has been conducted and that the conclusion of
the test was to reject the null hypothesis. Identify the population to which the results of the test apply.
A. The population is all shy workers.
B. The population cannot be identified from the description of the study.
C. The population is all American workers.
D. The population is all American professional workers (doctors, lawyers, CPA’s, and the like..
ANSWER B
12. A two-tailed test is conducted at the 0.10 significance level. What is the P-value required to reject the null
hypothesis?
A. Greater than or equal to .010
B. Greater than or equal to 0.05
C. Less than or equal to 0.10
D. Less than or equal to 0.05 ANSWER D
13. A nationwide study of American homeowners revealed that 65% have one or more lawn mowers. A lawn
equipment manufacturer, located in Omaha, feels the estimate is too low for households in Omaha. Find the Pvalue for a test of the claim that the proportion with lawn mowers in Omaha is higher than 65%. Among 497
randomly selected homes in Omaha, 340 had one or more lawn mowers. Use Table 5.1 to find the best
answer.
A. 0.0559
B. 0.1118
C. 0.0252
D. 0.0505
ANSWER A
14. A consumer advocacy group claims that the mean amount of juice in a 16
ounce bottled drink is not 16 ounces, as stated by the bottler.
Determine the null and alternative hypotheses for the test described.
A.
H0: µ = 16 ounces
Ha: µ < 16 ounces B. H0: µ  16 ounces Ha: µ = 16 ounces C. H0: µ = 16 ounces Ha: µ > 16 ounces
D.
H0: µ = 16 ounces
ANSWER D
Ha: µ  16 ounces
15. A long-distance telephone company claims that the mean duration of long-distance telephone calls
originating in one town was greater than 9.4 minutes, which is the average for the state. Determine the
conclusion of the hypothesis test assuming that the results of the sampling do not lead to rejection of the null
hypothesis.
A. Conclusion: Support the claim that the mean is less than 9.4 minutes.
B. Conclusion: Support the claim that the mean is greater than 9.4 minutes.
C. Conclusion: Support the claim that the mean is equal to 9.4 minutes.
D. Conclusion: Do not support the claim that the mean is greater than 9.4 minutes.
ANSWER D
16. A researcher claims that the amounts of acetaminophen in a certain brand of cold tablets have a mean
different from the 600 mg claimed by the manufacturer. Test this claim at the 0.02 level of significance. The
mean acetaminophen content for a random sample of n = 41 tablets is 603.3 mg. Assume that the population
standard deviation is 4.9 mg.
A. Since the test statistic is greater than the critical z, there is sufficient evidence to accept the
null hypothesis and to support the claim that the mean content of acetaminophen is 600 mg.
B. Since the test statistic is greater than the critical z, there is sufficient evidence to reject the
null hypothesis and to support the claim that the mean content of acetaminophen is not 600 mg.
C. Since the test statistic is less than the critical z, there is sufficient evidence to reject the null
hypothesis and to support the claim that the mean content of acetaminophen is not 600 mg.
D. Since the test statistic is greater than the critical z, there is insufficient evidence to reject the
null hypothesis and to support the claim that the mean content of acetaminophen is not 600 mg.
ANSWER B
17. A two-tailed test is conducted at the 5% significance level. Which of the z-scores below is the smallest one
that leads to rejection of the null hypothesis?
A. 1.12
B. 1.48
C. 1.84
D. 2.15
ANSWER D
18. A two-tailed test is conducted at the 5% significance level. What is the left tail percentile required to
reject the null hypothesis?
A. 97.5%
B. 5%
C. 2.5%
D. 95%
ANSWER C
19. In 1990, the average duration of long-distance telephone calls originating in one town was 9.4 minutes. A
long-distance telephone company wants to perform a hypothesis test to determine whether the average
duration of long-distance phone calls has changed from the 1990 mean of 9.4 minutes. The mean duration for
a random sample of 50 calls originating in the town was 8.6 minutes. Does the data provide sufficient evidence
to conclude that the mean call duration, µ, is different from the 1990 mean of 9.4 minutes? Perform the
appropriate hypothesis test using a significance level of 0.01. Assume that = 4.8 minutes.
A. With a z of -1.2 there is sufficient evidence to conclude that the mean
value has changed from the 1990 mean of 9.4 minutes.
B. With a P-value of 0.2302 there is not sufficient evidence to conclude
that the mean value is less than the 1990 mean of 9.4 minutes.
C. With a P-value of 0.2302 there is sufficient evidence to conclude that
the mean value is less than the 1990 mean of 9.4 minutes.
D. With a z of –1.2 there is not sufficient evidence to conclude that the
mean value has changed from the 1990 mean of 9.4 minutes.
ANSWER A
20. A skeptical paranormal researcher claims that the proportion of Americans that have seen a UFO is less
than 1 in every one thousand. State the null hypothesis and the alternative hypothesis for a test of significance.
A.
H0: p = 0.001
Ha: p > 0.001
B.
H0: p = 0.001
Ha: p < 0.001 C. H0: p > 0.001
Ha: p = 0.001
D.
H0: p < 0.001 Ha: p = 0.001 Answer B 21. The margin of error in estimating the population mean of a normal population is E = 9.3 when the sample size is 15. If the sample size had been 25 and the sample standard deviation did not change, would the margin of error be larger or smaller than 9.3? A. Smaller. E increases as the square root of the sample size gets larger. B. Smaller. E decreases as the square root of the sample size gets larger. C. Larger. E decreases as the square root of the sample size gets larger. D. Larger. E increases as the square root of the sample size gets larger. Answer A 22. One hundred people are selected at random and tested for colorblindness to determine whether gender and colorblindness are independent. The following counts were observed. Colorblind Not Colorblind Total Male 8 52 60 Female 2 38 40 Total 10 90 100 If gender and colorblindness are independent, find the expected values corresponding to the four combinations of gender and colorblindness, and enter them in the following table along with row and column totals. Colorblind Not Colorblind Total Male Female Total A. Male Colorblind 6.0; Male Not Colorblind 54.0 B. Male Colorblind 7.0; Male Not Colorblind 53.0 C. Male Colorblind 8.0; Male Not Colorblind 52.0 D. Male Colorblind 6.0; Male Not Colorblind 53.0 ANSWER B 23. A golfer wished to find a ball that would travel more than 180 yards when hit with his 5-iron with a club speed of 90 miles per hour. He had a golf equipment lab test a low compression ball by having a robot swing his club 7 times at the required speed. State the null and alternative hypotheses for this test. A. H0: µ = 180; Ha: µ > 180
B.
H0: µ > 180; Ha: µ > 180
C.
H0: µ < 180; Ha: µ > 180
D.
H0: µ = 180; Ha: µ < 180 Answer is C 24. One hundred people are selected at random and tested for colorblindness to determine whether gender and colorblindness are independent. The critical value of X2 for a 2 x 2 table using a 0.05 significance level is 3.841. If the value of the X2 statistic is 3.427, state your conclusion about the relationship between gender and colorblindness. A. Do not reject H0. There is not sufficient evidence to support the claim that gender and colorblindness are related. B. Do not reject H0. There is sufficient evidence to support the claim that gender and colorblindness are related. C. Reject H0. There is not sufficient evidence to support the claim that gender and colorblindness are related. D. Reject H0. There is sufficient evidence to support the claim that gender and colorblindness are related Answer B 25. One hundred People are selected at random and tested for colorblindness to determine whether gender and colorblindness are independent. The following counts were observed. Colorblind Not Colorblind Total Male 8 52 60 Female 2 38 40 Total 10 90 100 State the null and alternative hypothesis for the test associated with this data. A. H0: Colorblindness and gender are dependent characteristics. Ha: Colorblindness and gender are not related in any way. B. H0: Colorblindness and gender are dependent characteristics. Ha: Colorblindness and gender are related in some way. C. H0: Colorblindness and gender are independent characteristics. Ha: Colorblindness and gender are not related in any way. D. H0: Colorblindness and gender are independent characteristics. Ha: Colorblindness and gender are related in some way. ANSWER B 26. One hundred People are selected at random and tested for colorblindness to determine whether gender and colorblindness are independent. The following counts were observed. Colorblind Not Colorblind Total Male 7 53 60 Female 1 39 40 Total 8 92 100 Find the value of the X2 statistic for the data above. A. 1.325 B. 1.318 C. 1.286 D. 1.264 Answer is D 27. A large test statistic F tells us that the sample means __________ the data within the individual samples, which would be unlikely if the populations means really were equal (as the null hypothesis claims). A. differ more than B. differ less than C. are equal to D. do not vary with Answer is A 28. A simple random sample from a normal distribution is taken in order to obtain a 95% confidence interval for the population mean. If the sample size is 8, the sample mean x̄ is 22, and the sample standard deviation s is 6.3, what is the margin of error? Show your answer to 2 decimal places. A. df = 7; E = 3.3445.38 = 5.6566 B. df = 8; E = 3.3445.38 = 5.6566 C. df = 6; E = 2.3656.38 = 5.769 D. df = 7; E = 2.3656.38 = 5.869 Answer is C 29. A golfer wished to find a ball that would travel more than 170 yards when hit with his 6-iron with a club head speed of 90 miles per hour. He had a golf equipment lab test a low compression ball by having a robot swing his club 12 times at the required speed. State the null and alternative hypotheses for this test. A. H0: µ > 170; Ha: µ = 170
B.
H0: µ < 170; Ha: µ = 170 C. H0: µ = 170; Ha: µ > 170
D.
H0: µ = 160; Ha: µ > 160
ANSWER B
30. One hundred people are selected at random and tested for colorblindness to determine whether gender
and colorblindness are independent. The following counts were observed.
Colorblind Not Colorblind Total
Male
7
53
60
Female
1
39
40
Total
8
92
100
If gender and colorblindness are independent, find the expected values corresponding to the female
combinations of gender and colorblindness.
A. Colorblind Female 4.8; Not Colorblind Female 55.2
B. Colorblind Female 3.2; Not Colorblind Female 36.8
C. Colorblind Female 4.8; Not Colorblind Female 35.2
D. Colorblind Female 3.8; Not Colorblind Female 36.2
ANSWER A
31. One hundred people are selected at random and tested for colorblindness to determine whether gender
and colorblindness are independent. The following counts were observed.
Colorblind Not Colorblind Total
Male
7
53
60
Female
1
39
40
Total
8
92
100
If gender and colorblindness are independent, find the expected values corresponding to the male
combinations of gender and colorblindness.
A. Colorblind Male 4.8; Not Colorblind Male 55.2
B. Colorblind Male 6.8; Not Colorblind Male 53.2
C. Colorblind Male 4.8; Not Colorblind Male 55.4
D. Colorblind Male 4.8; Not Colorblind Male 56.2
ANSWER A
32. A 95% confidence interval for the mean of a normal population is found to be 13.2 < µ < 22.4. What is the margin of error? A. 4.6 B. 4.4 C. 4.2 D. 5.6 ANSWER A 33. One hundred people are selected at random and tested for colorblindness to determine whether gender and colorblindness are independent. The following counts were observed. Colorblind Not Colorblind Total Male 7 53 60 Female 1 39 40 Total 8 92 100 State the null and alternative hypothesis for the information above. A. H0: Colorblindness and gender are dependent characteristics. Ha: Colorblindness and gender are related in some way. B. H0: Colorblindness and gender are independent characteristics. Ha: Colorblindness and gender are not related in any way. C. H0: Colorblindness and gender are dependent characteristics. Ha: Colorblindness and gender are not related in any way. D. H0: Colorblindness and gender are independent characteristics. Ha: Colorblindness and gender are related in some way. ANSWER B 34. The following data were analyzed using one-way analysis of variance. A 34 26 31 28 B 27 23 29 21 C 19 31 22 22 Which one of the following statements is correct? A. The purpose of the analysis is to determine whether the groups A, B, and C are independent. B. The purpose of the analysis is to test the hypothesis that the population means of the three groups are equal. C. The purpose of the analysis is to test the hypothesis that the population variances of the three groups are equal. D. The purpose of the analysis is to test the hypothesis that the sample means of the three groups are equal. ANSWER B 35 . 2.5 Points Question 35 of 40 A golfer wished to find a ball that would travel more than 160 yards when hit with his 7-iron with a club speed of 90 miles per hour. He had a golf equipment lab test a low compression ball by having a robot swing his club 8 times at the required speed. Data from this test resulted in a sample mean of 163.2 yards with a sample standard deviation of 5.8 yards. Assuming normality, carry out a hypothesis test at the 0.05 significance level to determine whether the ball meets the golfer’s requirements. Use the partial t-table below to solve this problem. Area in one tail 0.025 0.05 Area in two tails Degrees of Freedom n-1 6 7 8 9 0.05 0.10 2.447 2.365 2.306 2.262 1.943 1.895 1.860 1.833 A. Do not reject the null hypothesis. The data do not provide sufficient evidence that the average distance is greater than 160 yards. B. Reject the null hypothesis. The data does provide sufficient evidence that the average distance is greater than 160 yards. C. t= 1.2334; Critical value = 1.992 D. Insufficient information to answer this question. ANSWER A 6. One hundred people are selected at random and tested for colorblindness to determine whether gender and ... Purchase answer to see full attachment

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