Answer:
C - He substituted incorrectly when calculating the constant of variation.
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
Answer:
6
Step-by-step explanation:
The angle bisector divides the other segments proportionally. There are many ways the proportion can be written. One is ...
XN/NY = XA/AY
XN = NY×XA/AY = 4 × 18/12
XN = 6
Answer:
https://www.khanacademy.org/
Step-by-step explanation:
I am not entirely sure what you mean however if you sign up for this website and go to whichever grade level you need you can practice all you want
