Suppose 40% of the students in a university are baseball players. If a sample of 781 students is selected, what is the probability that the sample proportion of baseball players will be greater than 43%

Respuesta :

Answer:

[tex]P(p>0.43) = 0.0436[/tex]

Step-by-step explanation:

Given

[tex]p = 40\%[/tex] -- proportion of baseball players

[tex]n = 781[/tex] --- selected sample

Required

Determine P(p>43%)

First, calculate the z score using:

[tex]Z = \frac{\^{p}-p}{\sqrt{\frac{p(1-p)}{n}}}[/tex]

This gives:

[tex]Z = \frac{48\%-40\%}{\sqrt{\frac{40\% *(1 - 40\%)}{781}}}[/tex]

Convert % to decimal

[tex]Z = \frac{0.43-0.40}{\sqrt{\frac{0.40 *(1 - 0.40)}{781}}}[/tex]

[tex]Z = \frac{0.43-0.40}{\sqrt{\frac{0.40 *0.60}{781}}}[/tex]

[tex]Z = \frac{0.43-0.40}{\sqrt{\frac{0.24}{781}}}[/tex]

[tex]Z = \frac{0.03}{\sqrt{0.00030729833}}[/tex]

[tex]Z = \frac{0.03}{0.01752992669}[/tex]

[tex]Z = 1.71[/tex]

So:

[tex]P(p>0.43) = P(Z>1.71)[/tex]

[tex]P(p>0.43) = 1 - P(Z<1.71)[/tex]

[tex]P(p>0.43) = 1 - 0.9564[/tex]

[tex]P(p>0.43) = 0.0436[/tex]

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