In 1980 (before the era of in-vitro fertilization), there were 3,612,258 births in the United States (according to the U.S. Census Bureau), of which 68,339 births were to twins and 1,337 births were to triplets or more.
What was the probability of having multiples (twins or more) in 1980?
Enter as a percent but do not include the % sign. Round to the nearest tenth (e.g., x.x).
What was the probability of a woman giving birth to multiples twice in a row in the pre-IVF era? (Assume that the probabilities for 1980 are representative of the pre-IVF era.)
Enter as a percent but do not include the % sign. Round to 3 decimal places (e.g., .xxx).
If a woman had 10 births in her lifetime in the pre-IVF era, what was the chance that at least one of those births was to multiples? (Assume that the probabilities for 1980 are representative of the pre-IVF era.)
Enter as a percent but do not include the % sign. Round to the nearest tenth (e.g., xx.x).
1.9
12
To calculate the probability of having multiples (twins or more) in 1980, we can use the formula:
Probability = (Number of births to multiples / Total number of births) * 100
Given that there were 3,612,258 total births and 68,339 births to twins or more in 1980, we can calculate the probability as follows:
Probability = (68,339 / 3,612,258) * 100
Calculating this gives us a probability of approximately 1.89%.
Now, to calculate the probability of a woman giving birth to multiples twice in a row in the pre-IVF era, we need to multiply the probability of having multiples by itself:
Probability = (Probability of having multiples) * (Probability of having multiples)
Probability = 1.89% * 1.89%
Calculating this gives us a probability of approximately 0.035721%, which can be rounded to 0.036%.
Finally, to calculate the chance that at least one of the 10 births a woman had in her lifetime was to multiples, we can use the complement rule. The probability of having no multiples in all 10 births is:
Probability of no multiples = (1 - Probability of having multiples)^10
Probability of no multiples = (1 - 0.0189)^10
Calculating this gives us a probability of approximately 80.33%.
Using the complement rule, the chance that at least one of the 10 births was to multiples is:
Chance of at least one multiple = 100% - Probability of no multiples
Chance of at least one multiple = 100% - 80.33%
Calculating this gives us a chance of approximately 19.67%, which can be rounded to 19.7%.