I think the answer is A) stratified random sampling! Stratified random sampling is when sunsets of individuals are created based on similar criteria, which sounds the closest to the problem because stratified can split a group and does not have to be fully equal.
Non random sampling doesn’t fit because it’s clearly stated that it’s random.
Systematic random sampling is based on intervals in a group.
The next closest answer would be simple random, which is when a subset of individuals are chosen from a larger group with all having the same probability.
You start by finding the slope : y2 - y1 / x2 - x1
2 - 8 / 4 - (-16)
- 6 / 20
m = - 3 / 10
Point slope form : y - y1 = m( x- x1 )
You can pick either of the coordinates and substitute them in
POINT SLOPE FORM EQUATION : y - 8 = -3/10 ( x + 16 )
Simply add the two dosages together, (0.15+0.025) and the answer is 0.175 :)
The equation that matches the graph is the second one !