Answer:
Margin of error of 0.0485 hours.
Step-by-step explanation:
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
.
That is z with a pvalue of
, so Z = 1.96.
Now, find the margin of error M as such

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

The margin of error is of:



Margin of error of 0.0485 hours.
9668
Explanation:
18 ones, 18x1=18
15 hundreds, 15x100 =1500
15 tens, 15x10=150
8 thousands,8x1000=8000
8x1000=800018+1500+150+8000=9668
<em>Hope</em><em> this</em><em> answer</em><em> correct</em><em> </em><em>:</em><em>)</em>
Sorry i dont know the answer
Third option: Elsa lost four points on the last math quiz, and Marc lost seven points. How many total points did they lose?
Using the normal distribution, the area underneath the shaded region <u>between the two z-scores</u> is given by:
C. 0.6766.
<h3>Normal Probability Distribution</h3>
The z-score of a measure X of a normally distributed variable with mean
and standard deviation
is given by:

- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
Hence, for this problem, the area is the <u>p-value of z = 0.75 subtracted by the p-value of z = -1.3</u>.
Looking at the z-table, the p-values are given as follows:
Then:
0.7734 - 0.0968 = 0.6766.
Which means that option C is correct.
More can be learned about the normal distribution at brainly.com/question/15181104
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