Which two ratios form a proportion?
a) 1 : 4 and 5 : 20
b) 1 : 4 and 20 : 5

c) 4 : 1 and 20 : 4
d) 4 : 1 and 4 : 20

a)1 : 4 and 5 : 20

Step-by-step explanation:

If a ratio is a proportion that means the

quantity on the left hand side is lesser than the quantity on the right hand side; it's a part of a whole, a small fraction.

Example of proportion ratios:

4 : 7

7 : 29

90 : 200

68 : 140

Example of non-prpotion ratios:

7 : 4

80 : 19

29 : 20

the equation for this situation is y=122+45. to solve the equation you would add 45 and 122 to get a total of 167lbs. in conclusion, grace's weight eight weeks ago was 167lbs.  

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.