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: 12 cm
Step-by-step explanation:
The masses of the spheres are proportional to their volums, and the cube of the ratio is k^3=135/5=27 ==> k=3
The greater radius is 3*4=12 (cm)
4/10 would be 2/5 in simplest form.
I hope this helps! (:
Answer:
y + 1 = 7(x + 2).
Step-by-step explanation:
Point slope form:
y - y1 =m(x - x1).
Here m = 7 and (x1, y1) = (-2, -1)
So the answer is;
y - (-1) = 7(x - (-2))
