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A survey of businesses in a particular state found that out of 150 surveyed, 51 were owned by women. We want to estimate the true proportion of businesses owned by women.
Construct a 95% confidence interval. Round your answers to 4 decimal places.


Sagot :

Answer:

The 95% confidence interval for the true proportion of businesses owned by women is (0.2763, 0.4037).

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which

z is the zscore that has a pvalue of [tex]1 - \frac{\alpha}{2}[/tex].

A survey of businesses in a particular state found that out of 150 surveyed, 51 were owned by women.

This means that [tex]n = 150, \pi = \frac{51}{150} = 0.34[/tex]

95% confidence level

So [tex]\alpha = 0.05[/tex], z is the value of Z that has a pvalue of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].

The lower limit of this interval is:

[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.34 - 1.96\sqrt{\frac{0.34*0.66}{150}} = 0.2763[/tex]

The upper limit of this interval is:

[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.34 + 1.96\sqrt{\frac{0.34*0.66}{150}} = 0.4037[/tex]

The 95% confidence interval for the true proportion of businesses owned by women is (0.2763, 0.4037).