if we select a birth at random, what is the probability the mother is 19 years of age or younger
What groups are you considering? What country? What areas of the country? What socioeconomic levels?
More data needed.
To calculate the probability, we need information about the population distribution of ages for mothers giving birth. Since I do not have access to this specific data, I cannot provide an accurate probability without mentioned data.
However, if we assume a hypothetical distribution of ages, we can use that for illustration purposes. Let's suppose we have data indicating that 10% of mothers giving birth are 19 years of age or younger.
In this case, the probability of selecting a birth where the mother is 19 years of age or younger would be 0.10, or 10%.
Again, please note that this is just a hypothetical example. To obtain an accurate probability, you would need the real distribution of ages for mothers giving birth.