A women has 0.5 probability of having a baby with bih weight >= 3000 grams & 0.2 probability of having a baby with bih weight 2500-2999 grams. What is the probability that this women will have a baby with bih weight > 2.5 kilograms?
**Core Concept**
The question is testing the understanding of probability and its application to a specific clinical scenario. The concept of probability is crucial in medicine, especially in obstetrics, where the risk of certain conditions or outcomes needs to be accurately predicted.
**Why the Correct Answer is Right**
To solve this problem, we need to calculate the probability of the baby's birth weight being greater than 2.5 kilograms. This can be done by adding the probabilities of the baby's birth weight being greater than or equal to 3000 grams and the baby's birth weight being between 2500-2999 grams, as both of these scenarios result in a birth weight greater than 2.5 kilograms. The probability of the baby's birth weight being greater than or equal to 3000 grams is 0.5, and the probability of the baby's birth weight being between 2500-2999 grams is 0.2. Therefore, the total probability is 0.5 + 0.2 = 0.7.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not take into account the combined probability of both scenarios. If we only consider the probability of the baby's birth weight being greater than or equal to 3000 grams, we would miss the additional probability contributed by the baby's birth weight being between 2500-2999 grams.
**Option B:** This option is incorrect because it implies that the probability of the baby's birth weight being between 2500-2999 grams is 0.5, which is not the case.
**Option C:** This option is incorrect because it implies that the probability of the baby's birth weight being greater than 2.5 kilograms is less than 0.5, which contradicts the correct calculation.
**Option D:** This option is incorrect because it implies that the probability of the baby's birth weight being greater than 2.5 kilograms is 0.2, which is only the probability of the baby's birth weight being between 2500-2999 grams.
**Clinical Pearl / High-Yield Fact**
When dealing with probabilities in medicine, it's essential to consider all possible scenarios and their combined probabilities to arrive at an accurate conclusion.
**Correct Answer:** . **0.7**