Discussions 7-9 (Stastics)

Week 7 Discussion            

"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.
• Construct a hypothetical 95% confidence interval for a hypothetical case of your choosing. Use your own unique choice of mean, standard deviation, and sample size to calculate the confidence interval. Select one (1) option provided below and analyze what will happen to your confidence interval based on the option you selected:
  • The confidence changes to 90%.
  • The confidence changes to 99%.
  • The sample size is cut in half.
  • The sample size is doubled.
  • The sample size is tripled.

          Provide a rationale for your response

Week 8 Discussion

"You Can’t Prove the Null by Not Rejecting It" (Note: Please respond to one [1] of the following two [2] bulleted items)

• Debate if “failing to reject the null” is the same as “accepting the null.” Support your position with examples of acceptance or rejection of the null. Next, give your opinion on whether or not a failed t test “proves” the null hypothesis.   
• Take a position on this statement: In setting up a hypothesis test, the claim should always be written in the alternative hypothesis. Provide one (1) example to support your position.

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

• • Discuss what would happen to someone’s sleep if they choose to work more.
  • 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.