20 POINTS PLS ANSWER FAST- WILL GIVE BRAINLIEST Identify all the cases where non-probability sampling is used when attempting to study the characteristics of a large city.
- studies on every subject in the population
- divide a population in groups and obtain a sample
- studies with a limited amount of time
-demonstrate existing traits in a population
-studies with the nth person selec

16.9 times 2.85

step-by-step explanation:

step-by-step explanation:

hjkj

step-by-step explanation:

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for