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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.

User Maxjakob
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1 Answer

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Answer:

23.27%

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) =
P(z <\frac{x-p}{\sqrt{(p*(1-p))/(n) }})

Replacing we have:


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

P ( z < 0.73) = 1 - P ( z => 0.73)

= 1 - 0.7673

= 0.2327

Therefore the probability is 23.27%

At a cell phone assembly plant, 75% of the cell phone keypads pass inspection. A random-example-1
User TavoGLC
by
6.0k points
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