Question 2 (16 points)
Question 2 options:
David Lane: Page 365 Exercise 15
You take a sample of 22 from a population of test scores.
The mean of your sample is 60.
The population standard deviation is 10.
What is the point estimate for the population mean?
Enter answer as integer.
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What is the 99% confidence interval for the population mean?
Enter the lower number of the conference interval for the first number and the upper number of the conference interval for the second number.
Enter each number rounded to 2 decimal places.
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Assume you do not know the population standard deviation.
The sample standard deviation is 10.
What is the new 99% confidence interval on the mean?
Enter the lower number of the conference interval for the first number and the upper number of the conference interval for the second number.
Enter each answer rounded to 2 decimal places.
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What distribution did you use when computing the first confidence interval?
a The Normal distribution
b The t distribution
c The Uniform distribution
d Neither of the above distributions
Answer the question by selecting the proper letter a, b, c or d.
What is the degrees freedom for calculating the confidence interval?
Enter 0 if the question is no applicable for the distribution being used.
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What distribution did you use when computing the second confidence interval?
a The Normal distribution
b The t distribution
c The Uniform distribution
d Neither of the above distributions
Answer the question by selecting the proper letter a, b, c or d.
What is the degrees freedom for calculating the confidence interval?
Enter 0 if the question is not applicable for the distribution being used.
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Question 3 options:
David Lane: Page 365 Exercise 12
A person claims to be able to predict the outcome of flipping a coin. The person is correct 16/25 times.
What is the point estimate for the proportion of times the person predicted the coin flips correctly?
Enter answer as a fraction or a decimal with 2 decimal places with a zero to the left of the decimal point. Do not enter your answer in percent.
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What is the sample size for calculating a confidence interval for the proportion of heads demonstrated based upon the reported data?
Enter answer as an integer.
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Compute a 95% confidence interval for the proportion of times the person predicted the coin flips correctly.
Enter the lower number and the upper number for the confidence interval with the lower number first.
Enter answer as a decimal with 3 decimal places with a zero to the left of the decimal point.
Do not enter your answer in percent.
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What conclusion can you draw from the confidence interval about the ability of the person to predict the outcome of a coin flip?
Select the correct answer and enter the letter that is associated with that answer.
a Based upon the data, the calculated conference interval supports the claim that the person flipping the coins can predict the outcomes.
b Based upon the data, the calculated conference interval does not support the claim that the person flipping the coins can predict the outcomes.
c There is insufficient information to draw any conclusion from the experimental results
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What number must the lower number in the confidence interval exceed in order for the confidence interval to support the claim of being able to predict the outcome of flipping a coin?
Enter answer as a decimal to 1 decimal place with a 0 to the left of the decimal point.
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Question 4 options:
Illowsky: Page 457 Exercise 130
On May 23, 2013, Gallup reported that of the 1,005 people surveyed, 76% of U.S. workers believe that they will continue working past retirement age. The confidence level for this study was reported at 95% with a ±3% margin of error.
What is the estimated proportion of U.S. workers that believe that they will continue working past retirement age?.
What is the sample size that was used to determine the confidence interval?
Enter the values of the 2 variables in the same order in which they are asked.
Enter answer for the proportion as a decimal to 2 decimal places with a 0 to the left of the decimal point.
Enter the sample size as an integer.
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Which distribution should you use for this problem?
Select the correct distribution and enter the appropriate letter.
a Uniform distribution
b Normal distribution
c t distribution
d Chi Sq distribution
Enter the degrees of freedom (dF) for this problem.
If asking for the numerical value of the degrees of freedom (dF) for this problem is an inappropriate question ender the number 0
Enter the answers for the 2 questions being asked in the same order in which they were asked.
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Construct a 95% confidence interval for the proportion of U.S. workers that believe that they will continue working past retirement age..
Enter answer to 2 decimal places with a 0 to the left of the decimal place.
Enter the lower number of the confidence interval first followed by the upper number.
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What is meant by the term “95% confident” when constructing a confidence interval for a proportion?
a If we took repeated samples, approximately 95% of the samples would produce the same confidence interval.
b If we took repeated samples, approximately 95% of the confidence intervals would contain the true value of the population proportion.
c If we took repeated samples, approximately 95% of the confidence intervals would contain the sample proportion.
d If we took repeated samples, the sample proportion would equal the population proportion in approximately 95% of the samples.
Enter the correct answer by selecting the appropriate letter.
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Construct a 90% confidence interval for the proportion of U.S. workers that believe that they will continue working past retirement age.
Enter answer to 2 decimal places with a 0 to the left of the decimal place.
Enter the lower number of the confidence interval first followed by the upper number.
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Illowsky Page 505 Ex 77
An article in the San Jose Mercury News stated that students in the California state university system take 4.5 years, on average, to finish their undergraduate degrees.
Suppose you believe that the mean time is longer. You conduct a survey of 49 students and obtain a sample mean of 5.1 with a sample standard deviation of 1.2.
Using the above data you perform a hypothesis test to test your hypothesis at a 1% significance level?
Note: x ¯ is the sample average, typically referred to has xbar, an x with a horizontal line over it..
What is the null and alternate hypothesis for this hypothesis test?
Question 5 options:
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Ho: x ¯= 4.5, Ha: x ¯> 4.5 |
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Ho: μ ≥ 4.5, Ha: μ < 4.5 |
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Ho: μ = 4.75, Ha: μ > 4.75 |
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Ho: μ = 4.5, Ha: μ > 4.5 |
Question 6 options:
Illowsky Page 505 Ex 77. This is a continuation of Ex 77 in Illowsky
An article in the San Jose Mercury News stated that students in the California state university system take 4.5 years, on average, to finish their undergraduate degrees.
Suppose you believe that the mean time is longer. You conduct a survey of 49 students and obtain a sample mean of 5.1 with a sample standard deviation of 1.2 and then performa hypothesis at a 1% significance level.
To answer the above hypothesis test question, answer the following questions which follow the textbook procedure for performing a hypothesis test.
Note: The null and alternate hypotheses for this question are the answers to the previous question.
Critical value approach.
What is the numerical value of α for this test?
Enter answer as a decimal to 2 decimal places with a 0 to the left of the decimal point.
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What is the appropriate distribution for performing this test?
a. z distribution
b. t distribution
c. Either distribution
d. Neither. This question does not depend on knowing the appropriate distribution.
Select and enter the appropriate letter.
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What is the critical value for the test statistic?
Enter answer as a 3 place decimal (round answer to 3 decimal places)
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What is the numerical value of the test statistic?
Enter answer as a 1 place decimal.
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What is your decision based upon performing the Hypothesis test?
a There is insufficient evidence, based upon the data, to accept the alternate hypothesis.
b There is sufficient evidence, based upon the data, to accept the alternate hypothesis.
c It is not possible to make a decision (null or alternate), based upon the data.
d A strong case could be made for either decision (null or alternate) based upon the data.
Select and enter the appropriate letter.
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