At a cell phone assembly plant, 75% of the cell phone keypads pass inspection. A random sample of 110 keypads is analyzed. Find the probability that more than 78% of the sample keypads pass inspection. Use at least five decimal places for the denominator.

Respuesta :

Answer:

23.27%

Step-by-step explanation:

From the statement we know that random sample n is 110 and that p is 75% and x the percentage to evaluate is 78%

We have that the probability would be equal:

P (x > 0.78) =  [tex]P(z <\frac{x-p}{\sqrt{\frac{p*(1-p)}{n} }})[/tex]

Replacing we have:

[tex]P(z <\frac{0.78-0.75}{\sqrt{\frac{0.75*(1-0.75)}{110} }})[/tex]

P ( z < 0.73) =  1 - P ( z => 0.73)

= 1 - 0.7673

= 0.2327

Therefore the probability is 23.27%

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