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Verdich [7]
2 years ago
7

Researchers are concerned about the impact of students working while they are enrolled in classes, and they’d like to know if st

udents work too much and therefore are spending less time on their classes than they should be. First, the researchers need to find out, on average, how many hours a week students are working. They know from previous studies that the standard deviation of this variable is about 5 hours.A survey of 200 students provides a sample mean of 7.10 hours worked. What is a 95% confidence interval based on this sample?
Mathematics
1 answer:
antoniya [11.8K]2 years ago
6 0

Answer:

The 95% confidence interval based on this sample is =

[6.41, 7.79]

Step-by-step explanation:

The formula for Confidence Interval =

Mean ± z × standard deviation/√n

Sample mean = 7.1 hours

Standard deviation = 5 hours

n = 200 students

z = 95% confidence interval z score

= 1.96

C.I = 7.1 ± 1.96 × 5/√200

C.I = 7.1 ± 0.693

Hence, Confidence Interval

= 7.1 - 0.693

= 6.407

Approximately = 6.41

= 7.1 + 0.693

= 7.793

Approximately = 7.79

Therefore, the 95% confidence interval based on this sample is

[6.41, 7.79]

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I know the answer I got is wrong help.
irinina [24]

Answer:

∠2 = 18°

Step-by-step explanation:

∠WXZ = ∠1 + ∠2 ← substitute ∠1 = 3∠2

∠WXZ = 3∠2 + ∠2, that is

72 = 4∠2 ( divide both sides by 4 )

18 = ∠2, that is

∠2 = 18°

   

8 0
3 years ago
Plzzz help me with this I’ll give brainliest
scoray [572]

Answer18:

The quadrilateral ABCD is not a parallelogram

Answer19:

The quadrilateral ABCD is a parallelogram

Step-by-step explanation:

For question 18:

Given that vertices of a quadrilateral are A(-4,-1), B(-4,6), C(2,6) and D(2,-4)

The slope of a line is given m=\frac{Y2-Y1}{X2-X1}

Now,

The slope of a line AB:

m=\frac{Y2-Y1}{X2-X1}

m=\frac{6-(-1)}{(-4)-(-4)}

m=\frac{7}{0}

The slope is 90 degree

The slope of a line BC:

m=\frac{Y2-Y1}{X2-X1}

m=\frac{6-6}{(-4)-(-1)}

m=\frac{0}{(-3)}

The slope is zero degree

The slope of a line CD:

m=\frac{Y2-Y1}{X2-X1}

m=\frac{(-4)-6}{2-2}

m=\frac{-10}{0}

The slope is 90 degree

The slope of a line DA:

m=\frac{Y2-Y1}{X2-X1}

m=\frac{(-1)-(-4)}{(-4)-(2)}

m=\frac{3}{-6}

m=\frac{-1}{2}

The slope of the only line AB and CD are the same.

Thus, The quadrilateral ABCD is not a parallelogram

For question 19:

Given that vertices of a quadrilateral are A(-2,3), B(3,2), C(2,-1) and D(-3,0)

The slope of a line is given m=\frac{Y2-Y1}{X2-X1}

Now,

The slope of a line AB:

m=\frac{Y2-Y1}{X2-X1}

m=\frac{2-3}{3-(-2)}

m=\frac{-1}{5}

The slope of a line BC:

m=\frac{Y2-Y1}{X2-X1}

m=\frac{(-1)-2}{2-3}

m=\frac{-3}{-1}

m=3

The slope of a line CD:

m=\frac{Y2-Y1}{X2-X1}

m=\frac{0-(-1)}{(-3)-2}

m=\frac{-1}{5}

The slope of a line DA:

m=\frac{Y2-Y1}{X2-X1}

m=\frac{3-0}{(-2)-(-3)}

m=3

The slope of the line AB and CD are the same

The slope of the line BC and DA are the same

Thus, The quadrilateral ABCD is a parallelogram

3 0
3 years ago
A square concert stage in the center of a fairground has an area of 4x^2 + 12x +9 ft^2. The dimensions of the stage have the for
mezya [45]

Answer:

(8x+12) feet.The perimeter when x=2ft is 28 feet.

Step-by-step explanation:

The solution is in the attached file.

7 0
3 years ago
Given the function f(x) = 1/2x-3 and the domain {-4, 4, 10} what is the range of the function?
AlexFokin [52]

<h3><em>This is the range of y , Ry=R−{0}</em></h3>
3 0
3 years ago
The surface of a rectangular table has an area of 8 square feet and a perimeter of 12 feet. What are the dimensions of the table
nirvana33 [79]

Answer:

4 ft by 2 ft

Step-by-step explanation:

4*2=8

4+4+2+2=12

7 0
3 years ago
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