Answer :
Answer:
0.8809
Step-by-step explanation:
Given that:
The population proportion p = 4% = 4/100 = 0.04
Sample mean x = 16
The sample size n = 300
The sample proportion [tex]\hat p =\dfrac{x}{n}[/tex]
= 16/300
= 0.0533
∴
[tex]P(\hat p \leq 0.0533) = P\bigg ( \dfrac{\hat p - p}{\sqrt{\dfrac{P(1-P)}{n}}}\leq\dfrac{0.0533 - 0.04}{\sqrt{\dfrac{0.04(1-0.04)}{300}}}\bigg )[/tex]
[tex]P(\hat p \leq 0.0533) = P\bigg ( Z\leq\dfrac{0.0133}{\sqrt{\dfrac{0.04(0.96)}{300}}}\bigg )[/tex]
[tex]P(\hat p \leq 0.0533) = P\bigg ( Z\leq\dfrac{0.0133}{\sqrt{\dfrac{0.0384}{300}}}\bigg )[/tex]
[tex]P(\hat p \leq 0.0533) = P\bigg ( Z\leq\dfrac{0.0133}{\sqrt{1.28 \times 10^{-4}}}\bigg )[/tex]
[tex]P(\hat p \leq 0.0533) = P\bigg ( Z\leq\dfrac{0.0133}{0.0113}}\bigg )[/tex]
[tex]P(\hat p \leq 0.0533) = P\bigg ( Z\leq1.18}\bigg )[/tex]
From the z tables;
= 0.8809
OR
Let X be the random variation that follows a normal distribution;
Then;
population mean [tex]\mu[/tex] = n × p
population mean [tex]\mu[/tex] = 300 × 0.04
population mean [tex]\mu[/tex] = 12
The standard deviation [tex]\sigma = \sqrt{np(1-p)}[/tex]
The standard deviation [tex]\sigma = \sqrt{300 \times 0.04(1-0.04)}[/tex]
The standard deviation [tex]\sigma = \sqrt{11.52}[/tex]
The standard deviation [tex]\sigma = 3.39[/tex]
The z -score can be computed as:
[tex]z = \dfrac{x - \mu}{\sigma}[/tex]
[tex]z = \dfrac{16 -12}{3.39}[/tex]
[tex]z = \dfrac{4}{3.39}[/tex]
z = 1.18
The required probability is:
P(X ≤ 10) = Pr (z ≤ 1.18)
= 0.8809