Answer:
Option A)
z equals 0.60 minus 0.72 all over the square root of the quantity 0.72 times 0.28 over 80
Step-by-step explanation:
We are given the following in the question:
Sample size, n = 80
p = 72% = 0.72
[tex]\hat{p} = 60\5 = 0.60[/tex]
Formula for z-statistic:
[tex]z = \dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}[/tex]
Putting the values, we get,
[tex]z = \displaystyle\frac{0.60-0.72}{\sqrt{\frac{0.72(1-0.72)}{80}}}\\\\z =\displaystyle\frac{0.60-0.72}{\sqrt{\frac{0.72(0.28)}{80}}} = -2.39[/tex]
This, the correct answer is
Option A)
z equals 0.60 minus 0.72 all over the square root of the quantity 0.72 times 0.28 over 80