Answer:
The sample mean is
b.3.55
The margin of error is
0.32
Step-by-step explanation:
Deep explanation about a confidence interval
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
So it is z with a pvalue of
, so 
Now, find M as such

In which
is the standard deviation of the population and n is the size of the sample.

The lower end of the interval is the mean subtracted by M. So it is 6.4 - 0.3944 = 6.01 hours.
The upper end of the interval is the mean added to M. So it is 6.4 + 0.3944 = 6.74 hours.
In this problem:
The deep explanation is not that important.
We just have to recognize that the interval has a lower end and an upper end. The distance from both the upper and the lower end to the mean is M. This means that the sample mean is the halfway point between the lower end and the upper end.
The margin of error is the distance of these two points(lower and upper end) to the mean.
In our interval
Lower end: 3.23
Upper end: 3.87
Sample mean

So the correct answer is:
b.3.55
The margin of error is
3.87 - 3.55 = 3.55 - 3.23 = 0.32
Answer:
Step-by-step explanation:
prime factors of 20 = 2 * 2 * 5

Answer:
360°
Step-by-step explanation:
Each of the two triangles have 3 angles that add up to 180°.
So,
180° + 180° = 360°
The sum of the angles of a quadrilateral is 360°
Answer:
SAS (side-angle-side)
Step-by-step explanation:
In the given picture, it is shown that the triangles have two congruent sides, and one congruent angle between them. The congruent sides are shown by the lines on the sides. The congruent angle is shown by the box outlining the angle (technically a box outlining the angle demonstrates that the angle is a right angle, either way, it proves the congruency).
Answer:
Part A) 
Part B) 
Step-by-step explanation:
we know that
In a parallelogram, opposite angles are congruent and consecutive angles are supplementary
step 1
Find the value of x
we know that
----> by definition of parallelogram (opposite angles are congruent)
substitute the given values

solve for x

step 2
Find the measure of angle R

substitute the value of x

step 3
Find the measure of angle S
we know that
---> by definition of parallelogram (consecutive angles are supplementary)
we have

substitute


