Of college graduates, 18.4% smoke ciggerettes. What is the probability that more than 56 smoke from a sample of 280 graduates?
And.... last one...
What is the value of Z equal to the mean?
2006-11-08 04:44:07 · 5 answers · asked by Heather N 2 in Science & Mathematics ➔ Mathematics
first fin the mean with the sample of 280
multiply 280 to .184 to get the mean
multiply 280 to .184 and to .816 (from 1-.184) then take the
square root that will be your standard deviation
take the z score you will get ( 56 - 51.52 )/6.483851
=.6909 find teh valu in the standard normal distribution table
you will get 0.2549 subtract it from .5 because you need only
the probability higher than of 56 you will get
24.51%
2006-11-10 00:43:33 · answer #1 · answered by jdash01 3 · 0⤊ 0⤋
It is correct that of 280 you would expect 51.52 smokers on average(280*.184). To know what the probability of getting more than 56 I would think you would need to know the standard deviation. If it is greater than 2 standard deviations from 51.52 you would then have less than 3% chance of having more than 56 smokers.
2006-11-08 13:19:52 · answer #2 · answered by ciza29 3 · 0⤊ 0⤋
It's totally NOT what the person above said. Of course it's possible that you picked a sample that had more than 56%. You need to use a table of values to figure this problem out, and assume that this is a "normal distribution." I'm pretty sure that you must have the values for this somewhere... Good luck!
2006-11-08 13:09:55 · answer #3 · answered by Spanky M 2 · 0⤊ 0⤋
amountof smoker in this sample of 280=280*18.4%=51.52
pr of getting 56 =is ZERO because u cant get more than 51.52 from 280
its either that or u got the question wrong...
2006-11-08 12:56:59 · answer #4 · answered by Anonymous · 0⤊ 0⤋
OMG i should know this cause im taking SAT'S right now. But sorry i dont.....probability is so hard.
GOOD LUCK!!!!
2006-11-08 12:48:01 · answer #5 · answered by elena 2 · 0⤊ 0⤋