8. Decide if the situation involves permutations, combinations, or neither. Explain your reasoning. The number of ways you can choose 2 books from a selection of 8 to bring on vacation

The number of ways to choose 5 books =

(10*9*8*7*6) which can be also seen as 10!/5!

10!/5! Is If you're counting each order you select books as a different "way."

Meaning (abcde) is different from (abced)

For each of those 10!5!, sets of 5 books, there's 5! ways to order it, so one way to see the correct answer is to divide by the number of same re-orderings, and get 10!/5!5!

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.