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Brums [2.3K]
3 years ago
14

From past results, a professor knows that the test score of a student taking her final examination is a random variable with mea

n 65 and a variance known to be 15. What is the probability that a student will score between 50 and 80? (7-8.1.2)
(A) Somewhere between 0.75 and 0.85
(B) Exactly 0.6826
(C) Exactly 0.9333
(D) Somewhere between 0.55 and 0.75
Mathematics
1 answer:
umka2103 [35]3 years ago
8 0

Answer:

option B

Step-by-step explanation:

Given,

mean result (μ) = 65

standard deviation (σ)= 15

probability that student will score between 50 and 80

= P(50< x

= P(50< x

= P(50< x

 = P(Z < 1) - P(Z < -1)

Using z table,  

= 0.8413 - 0.1587

= 0.6826

the correct answer is option B

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A circular garden has a circumference of 113 yards. Lars is digging a straight line along a diameter of the garden at a rate of
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(113÷3.14)

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35.99÷9=3hrs 59min

7 0
3 years ago
Help please here is a picture:
Ivahew [28]

Answer:

<em>2 1/3, 2 1/4, 2 3/7</em>

Step-by-step explanation:

<u>Mixed Fractions</u>

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Some examples of mixed fractions are:

3 1/2, -4 5/8, 2 2/3

Between two consecutive integers a and a+1, there are infinitely many fractions. The centered number is a 1/2. Any number with its improper fraction part less than 1/2 is closer to a than to a+1.

In our problem, Jayne bought between 2 and 3 pounds of granola. We need to provide a mixed number that is closer to 2 pounds than to 3 pounds.

We can select any number with integer part 2 and a proper fraction less than 1/2.

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All of them are less than 2.5

6 0
3 years ago
Midpoint of (-3,2) (3,2)
Leno4ka [110]

Answer: (0, 2)

Step-by-step explanation:

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3 0
2 years ago
What is the sine value of 7 pi over 6? negative square root 3 over 2 square root 3 over 2 negative 1 over 2 1 over 2?
djverab [1.8K]
First thing to do is to change the radians to degrees so it's easier to determine our angle and where it lies in the coordinate plane.  \frac{7 \pi }{6} * \frac{180}{ \pi }=210.  If we sweep out a 210 degree angle, we end up in the third quadrant, with a 30 degree angle.  In this quadrant, x and y are both negative, but the hypotenuse, no matter where it is, will never ever be negative.  So the side across from the 30 degree reference angle is -1, and the hypotenuse is 2, so the sine of this angle, opposite over hypotenuse, is -1/2
6 0
3 years ago
Read 2 more answers
A small town of 1,000 people increases its population by 2,000 the grocery store raises its prices to match the new equilibrium
Alexxandr [17]

1. If a shift in demand and/or supply has taken place, identify the change and list the determinant.

Answer:

The answer is below

Step-by-step explanation:

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The determinant for this situation is the increase in demand

However, with the price increment, the will be an increase in supply.

7 0
2 years ago
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