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EleoNora [17]
3 years ago
15

A study uses a sample of 200 college students to learn about the number of hours they studied for their final exams. The mean nu

mber of hours was 136 and the standard deviation was 14 hours. If this data falls under a normal distribution or bell curve, which of the following statements is NOT true?
The number of students that studied 122 or fewer hours was about 32.

The number of students that studied 150 or fewer hours was about 168.

The majority of students studied between 122 and 150 hours.

No one studied less than 108 hours.
Mathematics
2 answers:
ZanzabumX [31]3 years ago
6 0
\displaystyle\mathbb P(X\le122)=\mathbb P\left(\frac{X-136}{14}\le\frac{122-136}{14}\right)=\mathbb P(Z\le-1)\approx0.1587
which means 0.1587\times200\approx32 studied 122 or fewer hours.

\displaystyle\mathbb P(X\le150)=\mathbb P\left(\frac{X-136}{14}\le\frac{150-136}{14}\right)=\mathbb P(Z\le1)\approx0.8413
which means 0.8413\times200\approx168 studied 150 or fewer hours.

So, neither of the first two are false.

Depending on your definition of "majority", you could also eliminate the third option. From the above calculations, you know that students that studied between 122 and 150 hours fall within 1 standard deviation of the mean, which corresponds to approximately 65% of the student population. "Majority" is often taken to mean "more than 50%", so this is also true.

This leaves us with the last option. For fun, let's compute that probability.
\displaystyle\mathbb P(X
which means 0.0228\times200\approx5 students studied less than 108 hours.
Dovator [93]3 years ago
4 0

Answer:

No one Studied less than 108 hours

Step-by-step explanation:

This is the answer because there were about 5 people that did study less than 108 hours! Hope this makes it easier to read

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DENIUS [597]

Answer:

The simplest ratio would be 5:3

Step-by-step explanation:

Both 10 and 6 can be divided by 2.

They turn into 5 and 3.

Since you can't make 5 and 3 any smaller, this will be the answer.

5:3

Hope this helped! :D

4 0
2 years ago
-4x-2y=-12<br> solve the system of equations
Blababa [14]
Um there needs to be another equation
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3 years ago
An ice cube is made of 5 fluid ounces of water. About how many milliliters of water does it take to make an ice cube
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<u>ANSWER: </u>

147.868 mL of water is required to make an ice cube.

<u>SOLUTION: </u>

Given that, an ice cube is made up of 5 fluid ounces of water.

We need to find how many milli liters of water does it require to make an ice cube.

For, that we have to convert 5 fluid ounces in to units of milli liters.

We know that, 1 US fluid ounce equals to 29.5735 milli liters. i.e. 1 US fluid ounce = 29.5735 mL

Now,  

An ice cube is made by 5 fluid ounces = 5 x 1 fluid ounce

= 5 x 29.5735 mL  = 147.868 mL

Hence, 147.868 mL of water is required to make an ice cube.

5 0
3 years ago
The function f(t) = t2 + 6t − 20 represents a parabola.
Novay_Z [31]
Part A: f(t) = t² + 6t - 20
              u = t² + 6t - 20
         + 20            + 20
      u + 20 = t² + 6t
u + 20 + 9 = t² + 6t + 9
      u + 29 = t² + 3t + 3t + 9
      u + 29 = t(t) + t(3) + 3(t) + 3(3)
      u + 29 = t(t + 3) + 3(t + 3)
      u + 29 = (t + 3)(t + 3)
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          - 29       - 29
              u = (t + 3)² - 29

Part B: The vertex is (-3, -29). The graph shows that it is a minimum because it shows that there is a positive sign before the x²-term, making the parabola open up and has a minimum vertex of (-3, -29).
------------------------------------------------------------------------------------------------------------------
Part A: g(t) = 48.8t + 28           h(t) = -16t² + 90t + 50
            | t |   g(t)  |                          |  t  |  h(t)  |
            |-4|-167.2|                          | -4 | -566 |
            |-3|-118.4|                          | -3 | -364 |
            |-2| -69.6 |                          | -2 | -194 |
            |-1| -20.8 |                          | -1 |  -56  |
            |0 |   -28  |                          |  0  |   50  |
            |1 |  76.8 |                          |  1  |  124 |
            |2 | 125.6|                          |  2  | 166  |
            |3 | 174.4|                          |  3  | 176  |
            |4 | 223.2|                          |  4  | 154  |
The two seconds that the solution of g(t) and h(t) is located is between -1 and 4 seconds because it shows that they have two solutions, making it between -1 and 4 seconds.

Part B: The solution from Part A means that you have to find two solutions in order to know where the solutions of the two functions are located at.
4 0
3 years ago
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Find the solution to the system of equations.
N76 [4]

Answer:

x = -2, y = 5.

Step-by-step explanation:

y=−4x−3

y=−2x+1

Because y is common to both left sides:

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-4x + 2x = 1 + 3

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x = 4/-2

x = -2.

So y = -4(-2) - 3

= 8 - 3

= 5 .

5 0
3 years ago
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