Prob of selected students times prob of selecting boys times prob of selecting 3 boys
total students = 15b + 30g = 45 students
1. 10s/45t = 0.22
2. 15b/45t = 0.33
3. 3b/15b = 0.2
0.22×0.33×0.2=0.0148
1.48%
I'm not sure 100%... double check answer please
For large sample confidence intervals about the mean you have:
xBar ± z * sx / sqrt(n)
where xBar is the sample mean z is the zscore for having α% of the data in the tails, i.e., P( |Z| > z) = α sx is the sample standard deviation n is the sample size
We need only to concern ourselves with the error term of the CI, In order to find the sample size needed for a confidence interval of a given size.
z * sx / sqrt(n) = width.
so the z-score for the confidence interval of .98 is the value of z such that 0.01 is in each tail of the distribution. z = 2.326348
The equation we need to solve is:
z * sx / sqrt(n) = width
n = (z * sx / width) ^ 2.
n = ( 2.326348 * 6 / 3 ) ^ 2
n = 21.64758
Since n must be integer valued we need to take the ceiling of this solution.
n = 22
5r-4 and r=-5 so it would be 5(-5)=-20, then -4 , so is is -24
D because it is a quadratic function
Answer:
15:20
15/20
15 to 20
there are 3 types of ways and there you go.
Step-by-step explanation:
have a great day ! :)
