Sample
9.23
A manufacturer of chocolate candies uses machines to package candies as they move along a filling line. Although the packages are labeled as 8 ounces, the company wants the packages to contain a mean of 8.17 ounces so that virtually none of the packages contain less than 8 ounces. A sample of 50 packages is selected periodically, and the packaging process is stopped if there is evidence that the mean amount packaged is different from 8.17 ounces. Suppose that in a particular of 50 packages, the mean amount dispensed is 8.159 ounces, with a sample standard deviation of 0.051
A. Is there evidence that the population mean amount is different from 8.17 ounces? (Use a 0.05 level of significance.)
B. Determine the p-value and
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C. Interpret the meaning of the p-value in (b).
D. Compare your conclusions in (a) and (b).
9.53
The U.S. Department of Education reports that 46% of full-time college students are employed while attending college (data extracted from “The Condition of Education 2009,” National Center for Education Statistics, nces.ed.gov). A recent survey of 60 full-time students at Miami University found that 29 were employed.
A. Use the five-step p-value approach to hypothesis testing and a 0.05 level of significance to determine whether the proportion of full-time students at Miami University is different that the national norm of 0.46.
B. Assume that the study found that 36 of the 60 full-time students were employed and repeat (a). Are the conclusions the same?
9.55
One of the issues facing organizations is increasing diversity throughout the organization. One of the ways to evaluate an organization’s success at increasing diversity is to compare the percentage of employees in the organization in a particular position with a specific background to the percentage in a position with that specific background in the general workforce. Recently, a large academic medical center determined that 9 of 17 employees in a particular position were female, whereas 55% of the employees for this position in the general workforce were female. At the 0.05 level of significance, is there evidence that the proportion of females in this position at this
So, we should reject the null hypothesis H0. At a 0.05 level of significance level, we conclude that there is a significant difference between the average height for females and the average height for the males.
Alene Semuels is a writer for The Atlantic, and formerly wrote for The Los Angeles Times, Boston Globe, and the Pittsburgh Post-Gazette. The author's purpose for writing this article was to inform college students and the public about opportunities to work while in college. Also it shows college students that working a full time job might not be the wisest thing to do while attending college full time. When this article was written, there was a new trend beginning to arise. In 2015, Georgetown University did a study of students who worked while in college. They found that 70 percent of students were employed while in college and 25 percent of those students are working full time while simultaneously going to college full time. Both the Chicago Tribune and CNBC wrote articles about the findings in the Georgetown study. Putting these things together, Semuels felt persuaded to talk about the topic from two
Findings and Conclusion: This research shows that women are still unrepresented in top management globally. The difference in performance of the companies in the same country and same industry implies that diversity serves a competitive differentiator. Certain companies focus on gender diversity and others focus on ethnic and racial diversity but no company in the top quartile focus on both. Companies which have greater diversity are able to attract top talent, improve internal and external customer satisfaction, improve decision making and hence improve
Because the p-value of .035 is less than the significance level of .05, I will reject the null hypothesis at 5% level.
Topics Distribution of the sample mean. Central Limit Theorem. Confidence intervals for a population mean. Confidence intervals for a population proportion. Sample size for a given confidence level and margin of error (proportions). Poll articles. Hypotheses tests for a mean, and differences in means (independent and paired samples). Sample size and power of a test. Type I and Type II errors. You will be given a table of normal probabilities. You may wish to be familiar with the follow formulae and their application.
Given the following information, would your decision be to reject or fail to reject the null hypothesis? Setting the level of significance at .05 for decision making, provide an explanation for your conclusion.
e. Now for the same data, Test the hypothesis that the median value of the difference in weights before and after the dieting programme is non-existent. What is the name of this test? Also state what the symmetric CI for the median of the difference would be.
Two studies are conducted to compare the experiences of seniors living in high-rise public housing to those of seniors living in townhouses with subsidized rent. The first study interviews 40
The customers in this case study have complained that the bottling company provides less than the advertised sixteen ounces of product. They need to determine if there is enough evidence to conclude the soda bottles do not contain sixteen ounces. The sample size of sodas is 30 and has a mean of 14.9. The standard deviation is found to be 0.55. With these calculations and a confidence level of 95%, the confidence interval would be 0.2. There is a 95% certainty that the true population mean falls within the range of 14.7 to 15.1.
Quality Associates, Inc. is a consulting firm that advises its clients about sampling and statistical procedures that can be used to control manufacturing processes. In one case, a client provided Quality Associates with a sample of 800 observations that were taken during a time when the client's process was operating satisfactorily. The sample standard deviation for these data was .21, hence, the population standard deviation was assumed to be .21. Quality Associates then suggested that random samples of size 30 be taken periodically to monitor the process on an ongoing basis. By analyzing the new samples, the client could quickly learn whether the process was operating satisfactorily. When the process was not operating
With a P-value of 0.00, we have a strong level of significance. No additional information is needed to ensure that the data given is accurate.
c. Then find the 95% confidence interval for the difference between proportions. From this confidence interval, can we conclude that there is a significant difference in the proportions?
(14.87*16/0.550329055/5.4772 = 0.1005) So, we have p = 0.1005. Then we ask if p is greater than a (alpha). Since p is greater than a = 0.10 we decide that there is significant evidence supporting the claim to not reject the Ho. So, we accept the null hypothesis that on average there is less than the advertised 16oz in each bottle.
Harvard Business Review September, 1996 / October, 1996 HEADLINE: MAKING DIFFERENCES MATTER: A NEW PARADIGM FOR MANAGING DIVERSITY BYLINE: by David A. Thomas and Robin J. Ely; David A. Thomas is an associate professor at the Harvard Business School in Boston, Massachusetts. Robin J. Ely is an associate professor at Columbia University 's School of International and Public Affairs in New York City. Their research and teaching focus on the influence of race, gender, and ethnicity on career dynamics and organizational effectiveness. ABSTRACT: MAKING DIFFERENCES MATTER: A NEW PARADIGM FOR MANAGING DIVERSITY DAVID A. THOMAS and ROBIN J. ELY Diversity efforts in the workplace have been undertaken with great goodwill, but, ironically, they often
b) The same article reported the mean size was more than 2100 square feet? Can we conclude that the mean size of homes sold in the Gulshan area is more than 2100 square feet? Use the 0.05 significance level. What is the