Question description

 

Week 7 

"Confidence Intervals" (Note: Please respond to one [1] of the following two [2] bulleted items)

•The vast majority of the world uses a 95% confidence in building confidence intervals. Give your opinion on why 95% confidence is so commonplace. Justify your response. 
OR

•Being able to understand and critically think about statistics presented to you is an important skill in your career. Find a published study of a research subject on which you might need to rely in your expected career which includes a margin of error as part of the report. 
•Discuss what the margin of error means as applied to your selected poll or survey and how how that information provides additional information beyond the point estimates reported. Be sure to include the link to your selected survey or poll.

Week 8 

"When does one use a one-tailed test or a two tailed test"

•In this week's Internet Resources, view tab 3. Sal sets up an example of a one-tailed hypothesis test and two-tailed hypothesis test. It is interesting to watch. Now create you own example showing when you would do a one-tailed test and when you would do a two-tailed test.

Week 9 Discussion 

"Correlation and Regression" (Note: Please respond to one [1] of the following two [2] bulleted items):

•Debate the following statement: "Correlation means Causation." Determine whether this statement is true or false, and provide reasoning for your determination, using the Possible Relationships Between Variables table from your textbook.
•Biddle and Hamermesh (1990) built a multiple regression model to study the tradeoff between time spent in sleeping and working and to look at other factors affecting sleep:
Sleep = β0 + β1 totwrk + β2 educ + β3 age + ε

where sleep and totwrk (total work) are measured in minutes per week and educ and age are measured in years. Suppose the following equation is estimated:

Sleep = 3500 – 0.15 totwrk – 11.20 educ + 2.29 age + ε

Week 10 

"Testing the Difference Between Two Means." (Note: Please respond to one [1] of the following two [2] bulleted items)

•What two assumptions must be met when you are using the z test to test differences between two means? Can the sample standard deviations s1 and s2 be used in place of the population standard deviations σ1 and σ2?
•Retired workers and disabled workers both receive Social Security benefits. What information would we need to test the claim that the difference in monthly benefits between the two groups is greater than $30 at the 0.05 level of significance? Write out the hypotheses and explain the testing procedure.

◦Discuss what would happen to someone’s sleep if they choose to work more.
â—¦Analyze whether the factors of totwrk, educ, and age are enough factors to explain the variation in sleep. Explain which additional factors should be explored in order to explain the variation in sleep. Provide your reasoning.