A two-tailed test is conducted at the 5% significance level. What is the left tail percentile required to reject the null hypothesis?
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.
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 right-tailed test is conducted at the 5% significance level. Which of the following z-scores is the smallest one in absolute value that leads to rejection of the null hypothesis?
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 s = 4.8 minutes.
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 manufacturer claims that the mean amount of juice in its 16 ounce bottles is 16.1 ounces. A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this. The mean volume of juice for a random sample of 70 bottles was 15.94 ounces. Do the data provide sufficient evidence to conclude that the mean amount of juice for all 16-ounce bottles, µ, is less than 16.1 ounces? Perform the appropriate hypothesis test using a significance level of 0.10. Assume that s = 0.9 ounces.
A two-tailed test is conducted at the 0.10 significance level. What is the P-value required to reject the null hypothesis?
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.
In 1990, the average duration of long-distance telephone calls originating in one town was 9.3 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 9.3 minutes. Formulate the null and alternative hypotheses for the study described.
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 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.
The owner of a football team claims that the average attendance at home games is over 3000, and he is therefore justified in moving the team to a city with a larger stadium. 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.
without computing a P-value, determine whether the alternate hypothesis is supported and give a reason for your conclusion.
A two-tailed test is conducted at the 5% significance level. What is the P-value required to reject the null hypothesis?
z = 1.8 for Ha: µ > claimed value. What is the P-value for the test?
Question 17 of 40 |
2.5 Points |
is less than 1 standard deviation above the claimed mean.
is less than 1 standard deviation above the claimed mean.|
A. Conclusion: Support the claim that the mean is less than 9.4 minutes.
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B. Conclusion: Support the claim that the mean is greater than 9.4 minutes.
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C. Conclusion: Support the claim that the mean is equal to 9.4 minutes.
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D. Conclusion: Do not support the claim that the mean is greater than 9.4 minutes.
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Question 18 of 40 |
2.5 Points |
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A. 0.0559
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B. 0.1118
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C. 0.0252
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D. 0.0505
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Question 19 of 40 |
2.5 Points |
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A. There is sufficient evidence to support the claim that the true proportion is less than 29 percent.
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B. There is not sufficient evidence to support the claim that the true proportion is greater than 29 percent.
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C. There is sufficient evidence to support the claim that the true proportion is equal to 29 percent.
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D. There is sufficient evidence to support the claim that the true proportion is greater than 29 percent.
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Question 20 of 40 |
2.5 Points |
In the past, the mean running time for a certain type of flashlight battery has been 9.8 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 = 9.8 hours
Ha : µ > 9.8 hours
Suppose that the results of the sampling lead to rejection of the null hypothesis. Classify that conclusion as a Type I error, a Type II error, or a correct decision, if in fact the mean running time has not increased.
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A. Type I error
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B. Type II error
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C. Correct decision
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D. Can not be determined from this information
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Question 21 of 40 |
2.5 Points |
The following data were analyzed using one-way analysis of variance.
| A | B | C |
| 34 | 27 | 19 |
| 26 | 23 | 21 |
| 31 | 29 | 22 |
| 28 | 21 | 12 |
Which one of the following statements is correct?
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A. The purpose of the analysis is to determine whether the groups A, B, and C are independent.
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B. The purpose of the analysis is to test the hypothesis that the population means of the three groups are equal.
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C. The purpose of the analysis is to test the hypothesis that the population variances of the three groups are equal.
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D. The purpose of the analysis is to test the hypothesis that the sample means of the three groups are equal.
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Question 22 of 40 |
2.5 Points |
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A. differ more than
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B. differ less than
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C. are equal to
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D. do not vary with
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Question 23 of 40 |
2.5 Points |
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.
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A. 1.325
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B. 1.318
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C. 1.286
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D. 1.264
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Question 24 of 40 |
2.5 Points |
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.
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A.
Do not reject H0. There is not sufficient evidence to support the claim that gender and colorblindness are related. |
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B.
Do not reject H0. There is sufficient evidence to support the claim that gender and colorblindness are related. |
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C.
Reject H0. There is not sufficient evidence to support the claim that gender and colorblindness are related. |
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D.
Reject H0. There is sufficient evidence to support the claim that gender and colorblindness are related. |
Question 25 of 40 |
2.5 Points |
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 |
0.05 | 0.10 |
| 6 | 2.447 | 1.943 |
| 7 | 2.365 | 1.895 |
| 8 | 2.306 | 1.860 |
| 9 | 2.262 | 1.833 |
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A.
Do not reject the null hypothesis. The data do not provide sufficient evidence that the average distance is greater than 160 yards. |
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B. Reject the null hypothesis. The data does provide sufficient evidence that the average distance is greater than 160 yards.
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C. t= 1.2334; Critical value = 1.992
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D. Insufficient information to answer this question.
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Question 26 of 40 |
2.5 Points |
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.
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A.
H0: Colorblindness and gender are dependent characteristics. Ha: Colorblindness and gender are related in some way. |
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B.
H0: Colorblindness and gender are independent characteristics. Ha: Colorblindness and gender are not related in any way. |
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C.
H0: Colorblindness and gender are dependent characteristics. Ha: Colorblindness and gender are not related in any way. |
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D.
H0: Colorblindness and gender are independent characteristics. Ha: Colorblindness and gender are related in some way. |
Question 27 of 40 |
2.5 Points |
Which of the following statements is true?
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A. The p distribution cannot be used when finding a confidence interval for the population mean with a small sample anytime the population standard deviation is unknown.
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B. The t distribution can be used when finding a confidence interval for the population mean with a small sample anytime the population standard deviation is unknown.
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C. The t distribution cannot be used when finding a confidence interval for the population mean with a small sample anytime the population standard deviation is unknown.
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D. The p distribution can be used when finding a confidence interval for the population mean with a small sample anytime the population standard deviation is unknown.
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Question 28 of 40 |
2.5 Points |
A 95% confidence interval for the mean of a normal population is found to be 15.6 < µ < 24.8. What is the margin of error?
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A. 4.4
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B. 4.6
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C. 4.8
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D. 5.0
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Question 29 of 40 |
2.5 Points |
A 95% confidence interval for the mean of a normal population is found to be 17.6 < µ < 23.6. What is the margin of error?
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A. 2.0
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B. 2.7
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C. 3.0
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D. 4.0
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Question 30 of 40 |
2.5 Points |
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?
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A. 4.6
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B. 4.4
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C. 4.2
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D. 5.6
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Question 31 of 40 |
2.5 Points |
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A. P-Value
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B. t
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C. F
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D. p
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Question 32 of 40 |
2.5 Points |
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.
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A. Colorblind Male 4.8; Not Colorblind Male 55.2
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B. Colorblind Male 6.8; Not Colorblind Male 53.2
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C. Colorblind Male 4.8; Not Colorblind Male 55.4
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D. Colorblind Male 4.8; Not Colorblind Male 56.2
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Question 33 of 40 |
2.5 Points |
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 18 and the sample standard deviation did not change, would the margin of error be larger or smaller than 9.3? Explain your answer.
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A. Smaller. E decreases as the square root of the sample size gets larger.
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B. Smaller. E increases as the square root of the sample size gets larger.
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C. Larger. E decreases as the square root of the sample size gets larger.
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D. Larger. E increases as the square root of the sample size gets larger.
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Question 34 of 40 |
2.5 Points |
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 |
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A. Male Colorblind 6.0; Male Not Colorblind 54.0
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B. Male Colorblind 7.0; Male Not Colorblind 53.0
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C. Male Colorblind 8.0; Male Not Colorblind 52.0
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D. Male Colorblind 6.0; Male Not Colorblind 53.0
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Question 35 of 40 |
2.5 Points |
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. State the null and alternative hypotheses for this test.
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A.
H0: µ = 160; Ha: µ > 150 |
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B.
H0: µ = 150; Ha: µ > 150 |
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C.
H0: µ = 160; Ha: µ > 160 |
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D.
H0: µ = 140; Ha: µ > 160 |
Question 36 of 40 |
2.5 Points |
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.
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A. df = 7; E = 3.3445.38 = 5.6566
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B. df = 8; E = 3.3445.38 = 5.6566
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C. df = 6; E = 2.3656.38 = 5.769
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D. df = 7; E = 2.3656.38 = 5.869
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Question 37 of 40 |
2.5 Points |
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.
Data from this test resulted in a sample mean of 184.2 yards and 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.
| Area in one tail | ||
| 0.025 | 0.05 | |
| Area in two tails | ||
| Degrees of
Freedom n – 1 |
0.05 | 0.10 |
| 6 | 2.447 | 1.943 |
| 7 | 2.365 | 1.895 |
| 8 | 2.306 | 1.860 |
| 9 | 2.262 | 1.833 |
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A.
Reject the null hypothesis. The data do not provide sufficient evidence that the average distance is greater than 180 yards. |
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B. Reject the null hypothesis. The data do provide sufficient evidence that the average distance is greater than 180 yards.
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C. Do not reject the null hypothesis. The data do provide sufficient evidence that the average distance is greater than 180 yards.
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D. Do not reject the null hypothesis. The data do not provide sufficient evidence that the average distance is greater than 180 yards.
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Question 38 of 40 |
2.5 Points |
Which of the following statements is true?
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A. The t distribution cannot be used when finding a confidence interval for the population mean with a small sample whenever the sample comes from a symmetric population.
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B. The t distribution can be used when finding a confidence interval for the population mean with a small sample whenever the sample comes from a symmetric population.
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C. The p distribution can be used when finding a confidence interval for the population mean with a small sample whenever the sample comes from a symmetric population.
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D. The p distribution can be used when finding a confidence interval for the population mean with a small sample whenever the sample comes from a symmetric population.
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Question 39 of 40 |
2.5 Points |
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 4.613, state your conclusion about the relationship between gender and colorblindness.
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A.
Reject H0. There is not sufficient evidence to support the claim that gender and colorblindness are related. |
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B.
Reject H0. There is sufficient evidence to support the claim that gender and colorblindness are related. |
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C.
Do not Reject H0. There is sufficient evidence to support the claim that gender and colorblindness are related. |
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D.
Do not Reject H0. There is not sufficient evidence to support the claim that gender and colorblindness are related. |
Question 40 of 40 |
2.5 Points |
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 3.179, state your conclusion about the relationship between gender and colorblindness.
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A.
Do not reject H0. |
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B.
Reject H0. |
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C.
There is sufficient evidence to support the claim that gender and colorblindness are not related. |
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D.
There is not sufficient evidence to accept or reject H0. |
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