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Aliun [14]
3 years ago
5

A teacher administers a standardized math test to his class of 75 students. The mean score (out of 300 possible points) is 235.

From previous studies, you know the population standard deviation is 28. Using the sample data given, calculate a 95% confidence interval for the population mean.
Mathematics
1 answer:
Ede4ka [16]3 years ago
8 0

Answer:

(228.663 ; 241.337)

Step-by-step explanation:

Given that:

Mean (m) = 235

Standard deviation (s) = 28

α = 95%

Zcritical at 95% = 1.96

Sample size (n) = 75

The confidence interval of the population mean can be obtained using the relation :

Mean ± Error

Error = Zcritical * (s/sqrt(n))

Error = 1.96 * (28/sqrt(75))

Error = 1.96 * 3.2331615

Error = 6.33699654

Error = 6.337

Lower boundary = 235 - 6.337 = 228.663

Upper boundary = 235 + 6.337 = 241.337

(228.663 ; 241.337)

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The axis of a great circle of a sphere is 24 inches. If its radius is 9 inches, how far is the plane of a section from the cente
Blababa [14]
A great circle is a section of a sphere that passes through its center. If the earth were a sphere, a great circle would be the equator and its axis would be the line connecting the geographic north and south pole. The length of the axis is then equal to the diameter of the sphere. For this problem, the radius of the sphere is 12 inches. A section is formed by slicing through the sphere and all sections of a sphere are circles. Considering the plane to be cut above and parallel with the equator (which is a great circle), the distance of the plane from the center of the sphere would then be the distance between the centers of the sphere and section. It is also given that the radius of the section is 9 inches. A right triangle is formed by connecting the center of the sphere, an edge of the section, and back to the center of the sphere whose hypotenuse is 12 inches (radius of the sphere), one leg is the 9 inches (radius of the section), and another leg is the distance of the plane from the sphere's center. Thus, the distance can be calculated using the Pythagorean theorem, d = sqrt(12^2 - 9^2) = sqrt(144 - 81) = sqrt(63) = 3*sqrt(7).


I hope my answer has come to your help. Thank you for posting your question here in Brainly.
6 0
3 years ago
Need help on 11, 12, and 13
Sati [7]
11. is 25°
(Both triangles have two congruent angles which means the 3rd angle is bound to be the same. Just add the 90° and the 65° to get 155 and subtract from 180° because all triangles equal 180°)
12. is 25°
(Same as before, two of the angles are congruent so the third one is the same. Add all of the angles together and have them equal 180° because their is a variable present. 2x+60+70=180 or 2x+130=180. subtract 130 from both sides to get the equation 2x=50 and then divide both sides by 2 to get x=25.)
13. y=14 and x=11.6 (assuming m<d says 15x ÷ 2 because I couldn't really read it)
(m<a = m<d and m<b = m<e because they are lined up together in the ABC and DEF equation. so 3y=42 and (15x÷2=87)
7 0
3 years ago
The sum of one-fifth of a number and two is five
Veseljchak [2.6K]

Answer:

15

Step-by-step explanation:

Let us first write an equation where the unknown number is represented with variable x. <em>The sum of a fifth of x and two is five:</em>

\frac{1}{5} x+2=5

Great! Let's solve for x by isolating the variable.

\frac{1}{5}x=3\\x=15

<u>Therefore, the unknown number is 15.</u>

<u />

<em>I hope this helps! Let me know if you have any questions :)</em>

3 0
3 years ago
I need the answer to this systems word problem. Step by step explanation please
algol [13]

Answer:

25 miles, and the cost will be $37.50.

Step-by-step explanation:

Mose's charge can be represented by f(x) = 0.5x + 25, Holly's charge can be represented by g(x) = 0.3x + 30.

Set the equations equal to each other: 0.5x + 25 = 0.3x + 30.

0.2x = 5

x = 25

Substitute 25 for x: f(x) = 0.5(25) + 25 = 37.5, g(x) = 0.3(25) + 30 = 37.5.

So f(x) = g(x) at x = 25, and the output will be 37.5.

6 0
2 years ago
What is the rate of change of equation x=9
Delicious77 [7]
Erm..

9 I guess..

Good luck?
5 0
3 years ago
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