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rosijanka [135]
3 years ago
14

A field test for a new exam was given to randomly selected seniors. The exams were graded, and the sample mean and sample standa

rd deviation were calculated. Based on the results, the exam creator claims that on the same exam, nine times out of ten, seniors will have an average score within 4% of 70%.
Is the confidence interval at 90%, 95%, or 99%? What is the margin of error? Calculate the confidence interval and explain what it means in terms of the situation.
Mathematics
1 answer:
swat323 years ago
4 0
All our answers lie in the above statement.

Confidence Level:
The creator claims that 9 out 10 students will have the average score in the said range. Or in other words we can say that the creator is 90% confident about the result of the field test. So the confidence level is 90%. 

Margin of Error:
The average score lies within 4% of 70%. This means the margin of error is 4% i.e. the average scores can deviate from 70% by 4% .

Confidence Interval:
Lower Limit = 70% - 4% = 66%
Upper Limit = 70% + 4% = 74%

Interpretation:
The exam creator is 90% confident that the average scores of seniors will be between 66% and 74%. 
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Answer:

23.13

Step-by-step explanation:

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A computer manufacturer shipped a total of 50 machines to its two warehouses, one in west and one in east. It cost 20$ per machi
Natalka [10]
E + w = 50.....w = 50 - e
25e + 20w = 1090

25e + 20(50 - e) = 1090
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5e = 90
e = 90/5
e = 18 <=== the east got 18

w = 50 - e
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Find the area of a circle whose area equals the half of the sum of the areas of two circles with radil 2 and 3.
OlgaM077 [116]

Step-by-step explanation:

step 1. a circle with r = 2 has area of (pi)r^2 = (pi)(4) = 4pi

step 2. a circle with r = 3 has area of (pi)r^2 = (pi)(9) = 9pi

step 3. the area, A, of a circle is half the sum of the area of the circles with r = 2 and r = 3

step 4. A = (4pi + 9pi)/2 = 13pi/2 = 6.5(pi).

step 5. the answer is not 6.5 but is 6.5(pi) or 6.5 times pi.

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3 years ago
If f(x)= x2 +1 and g(x)= 3x+1, find 2 - f(4).
Effectus [21]
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3 years ago
Determine whether each ordered pair is a solution to the inequality x+y&lt;−1.
polet [3.4K]

Answer:

Choice A.  (10, -1)
Choice B.  (-8, 9)
Choice D.  (6, -3)

Step-by-step explanation:

If we plug the coordinates of point A into the inequality, then we get,
x+y > -2

10 + (-1) > -2
9 > -2
That last inequality is a true statement since 9 is to the right of -2 on the number line. That means (10,-1) is a solution. Choice A is one of the answers.
Choices B and D are also answers
for similar reasons.
Something like choice C is not a solution because
x+y > -2
-1+(-9) > -2
-10 > -2
Which is false.
You should find that choice E is false as well.

If you graphed the inequality and all of the points mentioned (see below), then you can visually confirm the answers. Notice how points A, B and D are in the blue shaded region which is the solution set.
The point E on the boundary does not count as a solution. This is due to the lack of "or equal to" portion of the inequality sign. That visually shows point E is not a solution. Point C isn't a solution either as it's nowhere near the blue shaded region.

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2 years ago
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