sample statistic and a population parameter
? What is the difference between a sample statistic and a population parameter? Provide an example of each.
? What level of measurement is your year in college (freshman, sophomore, junior, or senior)? What level of measurement is your political affiliation? Would it make sense to calculate the mean, median and mode in these instances? Which would you recommend? Explain.
Week Two Discussion Questions
? Consider repair cost for Car A and Car B. The mean repair cost for each is $500 per year. Which statistics about repair cost may play into your decision to purchase one of these? Which car would you choose? Explain.
? At Stats High, there is a difficult exam that every junior takes. Over the last 5 years, the exam results are normally distributed with a mean of 35% and a standard deviation of 7%. If your friend takes the exam and receives a 58%, how would you explain to him how he did? What if he receives a 42%? Support your conclusion with probabilities and z-scores.
Week Three Discussion Questions
? Given a sample of housing prices in San Francisco and that you are selling a house, which estimator would be best to represent the average house price? Is this a biased or unbiased estimator? Justify your answer.
? Suppose you estimate the mean length of all popular songs to be 182 seconds. Then, you use a random sample of 40 songs from your iPod to construct a confidence interval. The confidence interval you construct is (182.2, 226.2). What can you conclude about your estimate based on this interval?
Week Four Discussion Questions
? Why would you use a z-test rather than a t-test? Which do you think you will use more often? Why?
? What is a P-value? What does a P-value of .0000001 mean?
Week Five Discussion Questions
? Part 1: The attached scatterplot shows the number of words spoken in a day by 56 couples ranging in age from 18 to 29, where the x values are the male number of words and the y values are the female number of words.
After viewing the attached scatterplot, do you think quiet males generally have chatty females as their partners, do chatty males generally have chatty females as their partners, or is there generally no relationship between the wordiness of males and their female partners? Why or why not? What is the statistical support for your answer?
Based only on the graph and not on your personal knowledge, do you think this data shows a strong positive correlation, a weak positive correlation, a strong negative correlation, a weak negative correlation, or no correlation? Estimate the value of r. Explain your answer.
? Part 2: Use the data from the first two columns of Data Set 17 in Appendix B in StatDisk to calculate the value of r, rounded to three decimal places. How did the calculated value compare with your estimate? If your calculated value was very different from your estimated value, what might account for the difference?