I got this wrong.
My method: 3+5+7+6/25 = 0.84
In the ETS review guide, to find the probability of X=3 children, they’ve basically executed it like this: 6/25. In case of at least 3 children, I am assuming it should be x < or equal to 3 and therefore adding all frequencies up to 3 children and then dividing that by total frequency. Let me know where I am going wrong please!
I don’t understand what you’re doing but you should make something like a probability mass function:
Now “at least three children” translates to \text{number of children} \geq 3, so you just add the probabilities from the table in correspondence to this.
\mathbb{P} (\text{Number of Children} \geq 3) = \frac{6}{25} + \frac{3}{25} + \frac{1}{25} = \frac {10}{25} = 0.4
Hey, I think I interpreted the question incorrectly and I assumed that it translated to number of children < or equal to 3. Thanks!
