a:
The test hypothesis.
a:
Explanation of Solution
The null hypothesis (H0) is
The unequal variance estimator (v) can be calculated as follows:
The value of unequal variance is 200.4, which can be round off as 200.
The t table value can be calculated as follows:
The t table value is 1.653.
The t value (t) can be calculated as follows:
The calculated t value is 0.62, and the p value is 0.2689. Since the p value is significantly different from 0, the alternate hypothesis is not accepted.
b:
The test hypothesis with decreasing standard deviation.
b:
Explanation of Solution
The unequal variance estimator (v) can be calculated as follows:
The value of unequal variance is 223.1, which can be round off as 223..
The t table value can be calculated as follows:
The t table value is 1.645.
The t value (t) can be calculated as follows:
The calculated t value is 2.46, and the p value is 0.0074. Since the p value is nearly equal to 0, the alternate hypothesis is accepted.
c:
The impact of decreasing standard deviation.
c:
Explanation of Solution
When the standard deviation decreases, it increases the calculated t value and decreases the p value.
d:
The test hypothesis with decreasing sample.
d:
Explanation of Solution
The unequal variance estimator (v) can be calculated as follows:
The value of unequal variance is 25.6, which can be round off as 26.
The t table value can be calculated as follows:
The t table value is 1.706.
The t value (t) can be calculated as follows:
The calculated t value is 0.23, and the p value is 0.4118. Since the p value is significantly different from 0, the alternate hypothesis is not accepted.
e:
The impact of decreasing sample.
e:
Explanation of Solution
When the
f:
The test hypothesis with decreasing mean value.
f:
Explanation of Solution
The unequal variance estimator (v) can be calculated as follows:
The value of unequal variance is 200.4, which can be round off as 200.
The t table value can be calculated as follows:
The t table value is 1.653.
The t value (t) can be calculated as follows:
The calculated t value is 0.35, and the p value is 0.3624. Since the p value is significantly different from 0, the alternate hypothesis is not accepted.
g:
The impact of decreasing mean value.
g:
Explanation of Solution
When the mean decreases, it decreases the t value and increases the p value.
Want to see more full solutions like this?
Chapter 13 Solutions
Statistics for Management and Economics (Book Only)
- You may need to use the appropriate appendix table technology to answer this question. Consider the following results for independent samples taken from two populations. Sample 1 Sample 2 = 400 n, = 300 P1 = 0.49 P2 = 0.35 (a) What is the point estimate of the difference between the two population proportions? (Use p, - P,.) 20.2 (b) Develop a 90% confidence interval for the difference between the two population proportions. (Use p, - p2. Round your answer to four decimal places.) 14.4 to 26 (c) Develop a 95% confidence interval for the difference between the two population proportions. (Use p, - p,. Round your answer to four decimal places.) 14.4 to 26 Need Help? Read It Master Itarrow_forwardThe following sample data are from a normal population: 12, 10, 14, 17, 15, 13, 8, 7. (a) What is the point estimate of the population mean? (b) What is the point estimate of the population standard deviation? (Round your answer to three decimal places.) (c) With 95% confidence, what is the margin of error for the estimation of the population mean? (Round your answer to one decimal place.)arrow_forwardThe table below shows data on a subsample of participants in the 7th examination of the Framingham Offspring Study. Characteristic n Sample Population Standard Мean Deviation Systolic Blood 10 121.2 11.1 Pressure Diastolic Blood 10 71.3 7.2 Pressure Total Serum 10 202.3 37.7 Cholesterol Weight 10 176.0 33.0 Height 10 67.175 4.205 Body Mass 10 27.26 3.10 Index Which of the following is the 95% confidence level for Systolic Blood Pressure 114.32, 128.08 120.98, 121.42 121.16, 121.24 112.16, 130.24arrow_forward
- Claim: The mean systolic blood pressure of all healthy adults is less than than 123 mm Hg. Sample data: For 275 healthy adults, the mean systolic blood pressure level is 122.96 mm Hg and the standard deviation is 15.62 mm Hg. The null and alternative hypotheses are Ho: μ = 123 and H₁: μ< 123. Find the value of the test statistic. The value of the test statistic is (Round to two decimal places as needed.)arrow_forwardQuestion: In a certain factory there are two independent processes manufacturing the same item. The average weight in a sample of 250 items produced from one process is found to be 120 ozs. with a standard deviation of 12 ozs. while the corresponding figures in a sample of 400 items from the other process are 124 and 14. Obtain the standard error of difference between the two sample means. Is this difference significant ? Also find the 99% confidence limits for the difference in the average weights of items produced by the two processes respectively.arrow_forwardIn your own words, discuss the relationship between a t-test and a confidence interval.arrow_forward
- A researcher is interested in determining if there is a relationship between exercise and blood pressure for adults over 50. A random sample of 236 adults over 50 is selected and the results are given below. Blood Pressure | Low Moderate High Exercise Walkers Non-walkers | 21 35 62 25 65 28 Test the claim that walking and blood pressure are independent. Use a= 0.01.arrow_forwardThe table below shows data on a subsample of participants in the 7th examination of the Framingham Offspring Study. Characteristic Sample Population Standard n Мean Deviation Systolic Blood 10 121.2 11.1 Pressure Diastolic Blood 10 71.3 7.2 Pressure Total Serum |Cholesterol 10 202.3 37.7 Weight 10 176.0 33.0 Height 10 67.175 4.205 Body Mass Index 10 27.26 3.10 Which of the following is the 95% confidence level for Total Serum Cholesterol 201.55, 203.05 202.15, 202.45 171.59, 233.01 178.93, 225.67arrow_forwardAssume that you have a sample of n, 8, with the sample mean X, 42, and a sample standard deviation of S, = 7, and you have an independent sample of n₂ = 13 from another population with a sample mean of X₂=35 and the sample standard deviation S₂ = 6. Complete parts (a) through (d) below. a. What is the value of the pooled-variance ISTAT test statistic for testing Ho: H+H2? ISTAT = (Round to two decimal places as needed.) b. In finding the critical value, how many degrees of freedom are there? degrees of freedom (Simplify your answer.) c. Using a significance level of a =0.05, what is the critical value for a one-tail test of the hypothesis Ho: H₁5 ₂ against the alternative H₁: ₁₂? The critical value is (Round to two decimal places as needed.) d. What is your statistical decision? OA. Do not reject Ho because the computed ISTAT test statistic is less than the upper-tail critical value. OB. Reject H, because the computed ISTAT test statistic is greater than the upper-tail critical value.…arrow_forward
- Question 1 The distance between the sample mean and the true population is the sampling error, O True Falsearrow_forwardWhen we estimate B1 without controlling for X2, we derived in class that the B1 we are able to estimate is B₁ =B₁ + B₂61 What term measures the size of the bias in our estimate? OB2d1 OB2 d1 OB1 4arrow_forwardIn an election, a news agency plans to collect a voter sample to determine the percentage of votes a candidate will receive. The agency find 40 persons vote for the candidate in a sample of 100 voters. (a) Can the agency conclude that the candidate will receive less than 50% of votes in the election at the a = 0.05 level of significance? (b) In the test of (a), what is the power of test if the true percentage of votes is 45%?arrow_forward
- Principles of Economics (12th Edition)EconomicsISBN:9780134078779Author:Karl E. Case, Ray C. Fair, Sharon E. OsterPublisher:PEARSONEngineering Economy (17th Edition)EconomicsISBN:9780134870069Author:William G. Sullivan, Elin M. Wicks, C. Patrick KoellingPublisher:PEARSON
- Principles of Economics (MindTap Course List)EconomicsISBN:9781305585126Author:N. Gregory MankiwPublisher:Cengage LearningManagerial Economics: A Problem Solving ApproachEconomicsISBN:9781337106665Author:Luke M. Froeb, Brian T. McCann, Michael R. Ward, Mike ShorPublisher:Cengage LearningManagerial Economics & Business Strategy (Mcgraw-...EconomicsISBN:9781259290619Author:Michael Baye, Jeff PrincePublisher:McGraw-Hill Education