In the general population in the US, identical twins occur at a rate of 30 per 1,000 live births. A survey records 10,000 births during Jan 2018 to Jan 2019 and found 400 twins in total. Which of the following are true?
1) The proportion of twin births during Jan 2018 to Jan 2019 is 0.03.
2) The proportion of twin births during Jan 2018 to Jan 2019 is 0.04.
3) The probability of twin births among the general population is 0.03.
4) The probability of twin births among the general population is 0.04.
5) Pr(observing a sample proportion of twin births from a random sample of 10,000 live births ≤ 0.04) = 0.03.
6) Pr(observing a sample proportion of twin births from a random sample of 10,000 live births ≤ 0.04) = 0.5.
7) Pr(observing a sample proportion of twin births from a random sample of 10,000 live births ≤ 0.03) = 0.04.
8) Pr(observing a sample proportion of twin births from a random sample of 10,000 live births ≤ 0.03) = 0.5.