Answer:
Step-by-step explanation:
.
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:
a) 18 grapefruits
b) 6 grapefruits
Step-by-step explanation:
a) n = 14.4 / 0.80 = 18 grapefruits
b) n = (14.4 / 3) / 0.8 = 6 grapefruits
Answer:
After 7 years, the value would be $9,046.
After 13 years, the value would be $3,660
Step-by-step explanation:
Hello from MrBillDoesMath!
Answer:
Solutions: x = +\- 5i or x = +\- sqrt(5)
Discussion:
Factor x^4 - 25:
x^4 - 25 = (x^2+5) (x^2-5) => factor x^2 - 5
x^4 - 25 = (x^2+5)(x + sqrt(5)) (x - sqrt(5)) => factor x^2 + 5
x^4 = 25 = (x +5i)(x-5i) (x + sqrt(5)) (x - sqrt(5))
Hence the solutions are
x = +\- 5i and x = +\- sqrt(5)
Thank you,
MrB
