(Random Sampling + Approximate Probability + Normal Approximation)
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Suppose that 16% of the population of the U.S. is left-handed. If a random sample of 130 people from the U.S. is chosen, approximate the probability that at least 20 are left-handed. Use the normal approximation to the binomial with a correction for continuity. Round your answer to at least three decimal places. Do not round any intermediate steps.
======================
MY CALCULATIONS:
0.16 x 130 = 20.8
Answer = 20.800?
probability statistics random
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$begingroup$
Suppose that 16% of the population of the U.S. is left-handed. If a random sample of 130 people from the U.S. is chosen, approximate the probability that at least 20 are left-handed. Use the normal approximation to the binomial with a correction for continuity. Round your answer to at least three decimal places. Do not round any intermediate steps.
======================
MY CALCULATIONS:
0.16 x 130 = 20.8
Answer = 20.800?
probability statistics random
$endgroup$
add a comment |
$begingroup$
Suppose that 16% of the population of the U.S. is left-handed. If a random sample of 130 people from the U.S. is chosen, approximate the probability that at least 20 are left-handed. Use the normal approximation to the binomial with a correction for continuity. Round your answer to at least three decimal places. Do not round any intermediate steps.
======================
MY CALCULATIONS:
0.16 x 130 = 20.8
Answer = 20.800?
probability statistics random
$endgroup$
Suppose that 16% of the population of the U.S. is left-handed. If a random sample of 130 people from the U.S. is chosen, approximate the probability that at least 20 are left-handed. Use the normal approximation to the binomial with a correction for continuity. Round your answer to at least three decimal places. Do not round any intermediate steps.
======================
MY CALCULATIONS:
0.16 x 130 = 20.8
Answer = 20.800?
probability statistics random
probability statistics random
asked May 8 '15 at 8:12
DinosaursDinosaurs
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First you have to use the cdf of the binomial distribution:
$P(X geq 20)=sum_{x=20}^{130}{130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{130-x} $
Applying converse probability
$P(X geq 20)=1-P(X leq 19)=1-sum_{x=0}^{19} {130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{1000-x} $
Approximation of the Binomial distribution by the Normal distribution:
$$P(X geq 20)=1-Phileft(frac{19+0.5-0.16cdot 130}{sqrt{130cdot 0.16 cdot 0.84}} right)$$
0.5 is the continuity correction factor. And $Phi(cdot)$ is the cdf of the Standard Normal distribution. You can do the approximation, because $ncdot p cdot (1-p) >9$ (rule of thumb).
I think you can proceed from here.
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1 Answer
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1 Answer
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$begingroup$
First you have to use the cdf of the binomial distribution:
$P(X geq 20)=sum_{x=20}^{130}{130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{130-x} $
Applying converse probability
$P(X geq 20)=1-P(X leq 19)=1-sum_{x=0}^{19} {130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{1000-x} $
Approximation of the Binomial distribution by the Normal distribution:
$$P(X geq 20)=1-Phileft(frac{19+0.5-0.16cdot 130}{sqrt{130cdot 0.16 cdot 0.84}} right)$$
0.5 is the continuity correction factor. And $Phi(cdot)$ is the cdf of the Standard Normal distribution. You can do the approximation, because $ncdot p cdot (1-p) >9$ (rule of thumb).
I think you can proceed from here.
$endgroup$
add a comment |
$begingroup$
First you have to use the cdf of the binomial distribution:
$P(X geq 20)=sum_{x=20}^{130}{130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{130-x} $
Applying converse probability
$P(X geq 20)=1-P(X leq 19)=1-sum_{x=0}^{19} {130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{1000-x} $
Approximation of the Binomial distribution by the Normal distribution:
$$P(X geq 20)=1-Phileft(frac{19+0.5-0.16cdot 130}{sqrt{130cdot 0.16 cdot 0.84}} right)$$
0.5 is the continuity correction factor. And $Phi(cdot)$ is the cdf of the Standard Normal distribution. You can do the approximation, because $ncdot p cdot (1-p) >9$ (rule of thumb).
I think you can proceed from here.
$endgroup$
add a comment |
$begingroup$
First you have to use the cdf of the binomial distribution:
$P(X geq 20)=sum_{x=20}^{130}{130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{130-x} $
Applying converse probability
$P(X geq 20)=1-P(X leq 19)=1-sum_{x=0}^{19} {130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{1000-x} $
Approximation of the Binomial distribution by the Normal distribution:
$$P(X geq 20)=1-Phileft(frac{19+0.5-0.16cdot 130}{sqrt{130cdot 0.16 cdot 0.84}} right)$$
0.5 is the continuity correction factor. And $Phi(cdot)$ is the cdf of the Standard Normal distribution. You can do the approximation, because $ncdot p cdot (1-p) >9$ (rule of thumb).
I think you can proceed from here.
$endgroup$
First you have to use the cdf of the binomial distribution:
$P(X geq 20)=sum_{x=20}^{130}{130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{130-x} $
Applying converse probability
$P(X geq 20)=1-P(X leq 19)=1-sum_{x=0}^{19} {130 choose x}cdot left(0.16right)^xcdotleft(0.84right)^{1000-x} $
Approximation of the Binomial distribution by the Normal distribution:
$$P(X geq 20)=1-Phileft(frac{19+0.5-0.16cdot 130}{sqrt{130cdot 0.16 cdot 0.84}} right)$$
0.5 is the continuity correction factor. And $Phi(cdot)$ is the cdf of the Standard Normal distribution. You can do the approximation, because $ncdot p cdot (1-p) >9$ (rule of thumb).
I think you can proceed from here.
answered May 8 '15 at 10:23


callculuscallculus
18.5k31428
18.5k31428
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