Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Hypothesis testing is one of the mainstays of medical research literature. You would be hard-pressed to find a research article in a clinical journal that doesn't contain the results of at least one hypothesis test. So it's important to think critically about hypothesis tests and what they mean--what they can and can't tell us about our data. I've presented three situations below. Write up a brief description of the problem with the conclusion drawn from the hypothesis test.
1. In an observational study of the effect of a physician quality reporting system, the mean age of the patients of physicians participating in the program is 72.675 years, while the mean age of the patients of physicians not participating in the program is 72.950 years. The total sample size is nearly 11,000 patients. The p-value for the hypothesis test that the mean ages are different is 0.001 (Null hypothesis: the difference in mean ages of the two groups is zero; alternative hypothesis: the difference in means is greater than or less than zero). The analyst concludes that the patients of physicians not participating in the program are older than the patients of participating physicians and therefore not a good comparison group for an observational study.
2. A 1999 study looked at the effect of exposure to perchlorate on rats' thyroids. 30 rats were exposed to perchlorate and their thyroids were compared to 30 rats not exposed to perchlorates. Two of the rats exposed to perchlorate were found to have a rare type of thyroid tumor. Zero of the rats not exposed to perchlorate had tumors. The experimenters performed a hypothesis test for the difference in number of tumors and got a p-value of 0.48. They concluded that perchlorate exposure does not cause thyroid tumors in rats.
3. Three psychiatrists studied a sample of schizophrenic and non-schizophrenic people. They measured 77 variables for each subject - religion, family background, childhood experiences etc. They wanted to determine what factors cause people to later become schizophrenic. Using their data they ran 77 hypothesis tests of the significance of the differences between the two groups of subjects, and found 2 significant at the 2% level. They immediately published their findings.
Determine whether each of the following is an experiment or an observational study. Also identify the explanatory and response variables.
The article claims that the distributions of annual returns for both common stocks and long-term government bonds are bell-shaped and approximately symmetric. Assume that these distributions are distributed as normal random variables with the mea..
Estimating the sample standard deviation using normal score - Find the sample standard deviation?
Find out the mean to the nearest whole number, for the following list of numbers: 20, 43, 67, 52, 67, 44, 62, 90, 21, 19, 15
Certain tubes manufactured by a company have a mean life of 800 hours and standard deviation of 60 hours. Find the probability that a random sample of 16 tubes taken from the group will have a mean life of?
Assume the life of these light bulbs follows a normal distribution. Find the probability that a random sample of 100 light bulbs will have an average life between 1760 and 1775 hours.
A radio station that plays classical music has a "By Request" program each Saturday night. The percentage of requests for composers on a particular night are listed below:
Determine whether each of the distributions given below represents a probability distribution. Justify your answer.
A check of dorm rooms on a large college campuses revealed that 38% had refrigerators, 52 percent had TVs and 21 percent had both a TV and a refrigerator. What's the probability that a randomly selected dorm room has.
Determine the class with the greatest number of data values.
A customer from Cavallaro's Fruit Stand picks a sample of 5 oranges at random from a crate containing 80 oranges, of which 6 are rotten. What is the probability that the sample contains 1 or more rotten oranges? (Round your answer to three decimal..
What is the probability that at least one of the alternations is discovered? Find the expected value and variance of the number of altered accounts discovered during the audit.
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd