The bureau of labor statistics reported that the average yearly income of dentists in the year 2009 was $110,000. a sample of 81 dentists, which was taken in 2010, showed an average yearly income of $120,000. assume the standard deviation of the population of dentists in 2010 is $36,000. a. we want to test to determine if there has been a significant increase in the average yearly income of dentists. provide the null and the alternative hypothesis. b. compute the test statistic. c. determine the p -value; and at 95% confidence, test the hypothesis.

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.

answer: 4 (:

step-by-step explanation:

step-by-step explanation: