Unit 4 Discussion

WHAT'S IN A SAMPLE?: WHAT'S IN A SAMPLE?: Why is it important that a

sample be random and representative when conducting hypothesis testing?

It is because of mathematical theorems which validate most hypothesis testing apply only to random samples (http://www.ma.utexas.edu). In other words, when we are accepting or rejecting the null hypothesis it is because of the random samples. While sampling can be a simple concept, it is also a very challenging process in operation. One of the many challenges is obtaining a sampling framework, which could be a list of action items in it, or members of, the population you want to study (Wolverton, 2009). Another thought could be that random sampling eliminates the bias by giving all subjects an equal chance to be chosen (http://www.ma.utexas.edu).

Reference

Wolverton, M. L. (2009). Research Design, Hypothesis Testing, and Sampling. Appraisal Journal, 77(4), 370-382.

Retrievd from http://www.ma.utexas.edu/users/mks/statmistakes/RandomSampleImportance.html

DISCUSSION QUESTION 1 -- TRUSTING THE RESULTS: If you were to read the

results of a study showing that daily use of a certain exercise machine

resulted in an average 10-pound weight loss, what more would you want to

know about the numbers in addition to the average? (Hint: Do you think

everyone who used the machine lost 10 pounds?) 

There is a lot of missing data to have a true understanding of what really happened with the weight loss. How long did the samples work out on the machine? What was the frequency of the sample? What kind of machine is the exercise equipment? Is the equipment aerobic or is it a weight machine? Did the samples go on a diet as well as work out? How long was the sample studied; was it a week, month, that information is lacking as well. I tend to lose weight quickly at first because I am a little overweight; therefore I would like to know what the average starting weight of the samples was. When doing research not all...