Answer:
The sample size required is 2500.
Step-by-step explanation:
z-score:
In function of the margin of error M, the z-score is given by:

In this question, we have that:

So






The sample size required is 2500.
I hope this is the answer you want
Answer:
The data can be modeled using linear equatins, because there's the same amount of population for fish A (+20 per year) and fish B (+30 per year) every year.
Cost/(number of cassettes) = $14.50/2 = x/15
Multiply by 15 to solve
15*($14.50/2) = x = $108.75
15 cassettes will cost $108.75.