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
Answere: I believe that the answere is C.
Step-by-step explanation:
Well,since the lines A and B are paralel and the line y is not paralel with any of then y and A are not paralel.Plus there is not a line called x in this particular equazion.If you have any questions , please contact me.
Yours sincerely,
Manos
0.00
*First column to your left - ones column (1)
*Column just after decimal place, in the middle - tenths column (1/10)
*Column to the far right - hundredths column (1/100)
The only numbers that can go in these columns are 0-9.
-------------
1.54 + 2.37
= (1 + 5/10 + 4/100) + (2 + 3/10 + 7/100)
= 1 + 5/10 + 4/100 + 2 + 3/10 + 7/100
= 3 + 8/10 + 11/100
= 3 + 8/10 + (10/100 + 1/100)
= 3 + 8/10 + (1/10 + 1/100)
= 3 + 8/10 + 1/10 + 1/100
= 3 + 9/10 + 1/100
= 3.91
Answer:
18) it is parallel to y axis