Answer:
a. 1.44
Step-by-step explanation:
We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 40%.
At the null hypothesis, it is tested if the proportion is of at most 40%, that is:

At the alternative hypothesis, it is tested if the proportion is of more than 40%, that is:

The test statistic is:
In which X is the sample mean,
is the value tested at the null hypothesis,
is the standard deviation and n is the size of the sample.
0.4 is tested at the null hypothesis:
This means that 
A random sample of 200 people was taken. 90 of the people in the sample favored Candidate A.
This means that:

Value of the test statistic:



Thus the correct answer is given by option a.
Answer:
9 · x - 16
Explanation:
Nine times a number: 9 · x
Decreased by 16: - 16
Put them together: 9 · x - 16
Answers:
Diameter - B)
Circumference - F)
Radius - C) or <span>E)*</span>
Secant - E) or C)*
Concentric circles - D)
Arc - A)
* Please, note that you described option C and option E with the same exact words. One of the two is supposed to be different.
Let's see the definition of each term of the list on the left in order to find the right description:
<em>Diameter</em> = any segment connecting two points on a circle passing through its center. Therefore, the correct description is B) a segment between two points on a circle that passes through its center.
<em>Circumference</em> = length of the distance around the circle (it's a sort of perimeter of the circle). Therefore, the correct description is F) the distance around a circle
<em>Radius</em> = constant distance from the center to any point on the circle. Therefore, the correct description is C/E) a line segment connecting the center C and a point B on the circle.
<em>Secant</em> = a<span> line that intersects a circle at any two points. Therefore the correct description is </span>E/C) Circle A and a line segment connecting the points B and C which are both on the circle.
<em>Concentric circles</em> = two circles positioned such as the center of the first one coincides with the center of the second one. Therefore the correct description is D) Two circles that share the same center.
<em>Arc</em> = part of the curve along the perimeter of a circle. Therefore, the correct description is A) a piece of the circumference of a circle.