What is the third quartile of this data set 21,24,25,28,2935,37,39,42

Definitions:

The third quartile, denoted by Q3 , is the median of the upper half of the data set. This means that about 75% of the numbers in the data set lie below Q3 and about 25% lie above Q3;

The upper half of a data set is the set of all values that are to the right of the median value when the data has been put into increasing order;

First, we verify data in increasing order:

21, 24, 25, 28, 29, 35, 37, 38, 42 ( okay);

The median is 29;

Therefore, the upper half of the data is {35, 37, 39, 42};

Q3 = ( 37 + 39 ) / 2 = 76 / 2 = 38;

Step-by-step explanation:

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.