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: It is A=-1<x<-6 is the domain
Answer:
161.92 is the radius
If you want, you can round it to 162 units
Convert to a mixed number:
239/42
Divide 239 by 42:
4 | 2 | 2 | 3 | 9
42 goes into 239 at most 5 times:
| | | | 5
4 | 2 | 2 | 3 | 9
| - | 2 | 1 | 0
| | | 2 | 9
Read off the results. The quotient is the number at the top and the remainder is the number at the bottom:
| | | | 5 | (quotient)
4 | 2 | 2 | 3 | 9 |
| - | 2 | 1 | 0 |
| | | 2 | 9 | (remainder)
The quotient of 239/42 is 5 with remainder 29, so:
Answer: 5 29/42
