Question 1194721
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You have the correct approximate z value
z = 1.960 when we have a 95% confidence level
For any future students curious how to find this value, you would use a table such as this one
<a href = "https://www.sjsu.edu/faculty/gerstman/StatPrimer/t-table.pdf">https://www.sjsu.edu/faculty/gerstman/StatPrimer/t-table.pdf</a>
Locate the "95%" in the bottom row. Just above that is 1.960
Alternatively, you can use a calculator to determine the value of z.


E = 0.015 is the decimal form of the 1.5% error we're after. We want this error or smaller.


p = 0.40 based on a previous study


n = min sample size needed
n = p*(1-p)*(z/E)^2
n = 0.40*(1-0.40)*(1.960/0.015)^2
n = 4097.70666666667 approximately
n = <font color=red>4098</font>
Always round up to the nearest whole number.
If we got something like 4097.00001, we still round up to the nearest whole number 4098 to ensure we clear the hurdle.


Answer: <font color=red>4098</font>
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