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:
your answer would be 190 all u do is add
Step-by-step explanation:
Answer:
137 + x <= 170
Step-by-step explanation:
The following inequality will describe this scenario.
137 + x <= 170
the variable x in this scenario represents the total number of cars that you will purchase. This number is added to the number of toy cars that you already own which is 137. As long as this sum is less than or equal to 170 then your storage case will hold them.
Answer:
Step-by-step explanation:
Given:
TU ≅ WU
∠T ≅ ∠W
To Prove:

Proof:
In Δ TUS and Δ WUV
STATEMENT REASON
1. TU ≅ WU 1. Given
2. ∠T ≅ ∠W 2. Given
3.∠TUS ≅ ∠WUV 3. Vertically Opposite Angles are equal
4. ΔTUS ≅ ΔWUV 4. Angle-Side-Angle congruence test.
5. ∴ TS ≅ WV 5. Corresponding parts of congruent triangles.
.......Proved
Answer: 8+18W
Step-by-step explanation:
1. First multiply the 4 by 2, equalling 8.
2. Then multiply the 9W by 2, equalling 18W.
3. 8 and 18W are unlike terms, so they can not be added together.
4. The answer would stay as 8+18W.