Answer:
a. .92
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
The margin of error of the interval is:

The lower bound is the point estimate
subtracted by the margin of error.
The upper bound is the point estimate
added to the margin of error.
Point estimate:
The confidence interval is symmetric, so it is the mean between the two bounds.
In this problem:

Sample of 400, which means that 
Margin of error is the estimate subtracted by the lower bound. So 
We have to find z.




has a pvalue of 0.96.
This means that:




Confidence level:

So the correct answer is:
a. .92
Answer:
Step-by-step explanation:
Area of sector = angle/360 * pi * r^2
5.5pi = angle/360 * pi * 9
5.5 = angle/360 * 9
angle = (5.5 * 360)/9 = 40 * 5.5 = 220
Ur answer will be C… basically u make the equation equal to zero and then use the quadratic formula to find ur answers…. x = -3 and 9
C - 11 /9 = 9
Multiply both sides by 9
c - 11 = 81
add 11 to each side to isolate c
c = 81 + 11 = 92