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Approximately 
20% of newborns are born more than 1 week before their due date. A random sample of 20 newborns is selected.
The standard deviation of the sampling distribution for the proportion of your sample that is born more than 7 days before their due date is
0.20 .
3.2 .
0.089 .
0.008 .

76.9% 76.9 \% \newlineResources\newlineCheck\newlineApproximately 20% 20 \% of newborns are born more than 11 week before their due date. A random sample of 2020 newborns is selected.\newlineThe standard deviation of the sampling distribution for the proportion of your sample that is born more than 77 days before their due date is\newline00.2020 .\newline33.22 .\newline00.089089 .\newline00.008008 .

Full solution

Q. 76.9% 76.9 \% \newlineResources\newlineCheck\newlineApproximately 20% 20 \% of newborns are born more than 11 week before their due date. A random sample of 2020 newborns is selected.\newlineThe standard deviation of the sampling distribution for the proportion of your sample that is born more than 77 days before their due date is\newline00.2020 .\newline33.22 .\newline00.089089 .\newline00.008008 .
  1. Use Formula: To find the standard deviation of the sampling distribution for the proportion, we use the formula for the standard deviation of a proportion, which is p(1p)/n\sqrt{p(1-p)/n}, where pp is the proportion and nn is the sample size.
  2. Plug Values: Given that p=20%p = 20\% or 0.200.20 and n=20n = 20, we plug these values into the formula: 0.20(10.20)/20\sqrt{0.20(1-0.20)/20}.
  3. Calculate Inside: Calculate the inside of the square root: 0.20×0.80/20=0.016/200.20 \times 0.80 / 20 = 0.016 / 20.
  4. Divide by 2020: Now divide 0.0160.016 by 2020: 0.016/20=0.00080.016 / 20 = 0.0008.
  5. Take Square Root: Finally, take the square root of 0.00080.0008: 0.0008=0.0283\sqrt{0.0008} = 0.0283, but we round to three decimal places, so the standard deviation is 0.0280.028.

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