A researcher wants to investigate the effects of environmental factors on IQ scores. For an initial study, she takes a sample of 400 people who grew up as the only child. She finds that 51.5% of them have an IQ score over 100. It is known that 50% of the general population has an IQ score exceeding 100. Answer the following. (If necessary, consult a list of formulas.) (a) Find the mean of p, where p is the proportion of people with IQ scores over 100 in a random sample of 400 people. (b) Find the standard deviation of p. (c) Compute an approximation for P(p20.515), which is the probability that there will be 51.5% or more individuals with IQ scores over 100 in a random sample of 400. Round your answer to four decimal places.

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A researcher wants to investigate the effects of environmental factors on IQ scores. For an initial study, she takes a sample of 400 people who grew up as the only child. She finds that 51.5% of them have an IQ score over 100. It is known that 50% of the general population has an IQ score exceeding 100.

Answer the following. (If necessary, consult a list of formulas.)

(a) Find the mean of \(\hat{p}\), where \(\hat{p}\) is the proportion of people with IQ scores over 100 in a random sample of 400 people.

[Box for answer]

(b) Find the standard deviation of \(\hat{p}\).

[Box for answer]

(c) Compute an approximation for \(P(\hat{p} \geq 0.515)\), which is the probability that there will be 51.5% or more individuals with IQ scores over 100 in a random sample of 400. Round your answer to four decimal places.

[Box for answer]
Transcribed Image Text:A researcher wants to investigate the effects of environmental factors on IQ scores. For an initial study, she takes a sample of 400 people who grew up as the only child. She finds that 51.5% of them have an IQ score over 100. It is known that 50% of the general population has an IQ score exceeding 100. Answer the following. (If necessary, consult a list of formulas.) (a) Find the mean of \(\hat{p}\), where \(\hat{p}\) is the proportion of people with IQ scores over 100 in a random sample of 400 people. [Box for answer] (b) Find the standard deviation of \(\hat{p}\). [Box for answer] (c) Compute an approximation for \(P(\hat{p} \geq 0.515)\), which is the probability that there will be 51.5% or more individuals with IQ scores over 100 in a random sample of 400. Round your answer to four decimal places. [Box for answer]
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From the given information, n = 400, p-hat = 0.515 and p = 0.50.

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