Is there any picture or something ?
We would need a sample size of 560.
We first calculate the z-score associated. with this level of confidence:
Convert 95% to a decimal: 95% = 95/100 = 0.95
Subtract from 1: 1-0.95 = 0.05
Divide by 2: 0.05/2 = 0.025
Subtract from 1: 1-0.025 = 0.975
Using a z-table (http://www.z-table.com) we see that this is associated with a z-score of 1.96.
The margin of error, ME, is given by:

We want ME to be 4%; 4% = 4/100 = 0.04. Substituting this into our equation, as well as our proportion and z-score,
The slope of the line l is the opposite reciprocal of y+2x=9. Rearranged the equation to y=9-2x and we get a slope of -2. The opposite reciprocal of -2 is 1/2.
y-y=m(x-x)
y-3=.5(x-4)
y=.5x+1
At the x-intercept, y=0, so
0=.5x+1
-1=.5x
x=-2
Step-by-step explanation:
2. Amount of soil provided.
In order to give different pH values of the soil, the amount of soil can directly affect this independent variable.