A recent study indicated that 35% of all dog owners have a retriever of some sort. If 300 dog owners are surveyed, what is the probability that at most 95 have a retriever of some sort? I need the steps to get to the answer. thank you!
2006-12-02 09:24:12 · 1 answers · asked by christinag1310 2 in Science & Mathematics ➔ Mathematics
Although this is really binomial because a dog owner either does or does not have a retriever. But , 300 is a large number so you can use the normal approximation.
For both the normal and the binomial you'd expect np=0.35*300 retrievers, this is your mean.
Now for SD, use the binomial expression:
SD= sqrt(np(1-p)) ,
Then get Z= (95-np)/SD
Since you want 'at most' that's P(z
If you know what the 'continuity correction' is then you can apply it. But I wouldn't worry about it here.
If you have a calculator that does it, you can do the exact calculation for the binomial and compare. I use a TI-83.
2006-12-02 09:31:40 · answer #1 · answered by modulo_function 7 · 1⤊ 0⤋