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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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HELP
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You did not provide any question. I will give general advice.

Pythagorean Theorem: a² + b² = c²

If you know two sides, you know ll three sides.

A house sits in the shade.

The house is 18 feet tall. The shadow is 24 feet long. What is the hypotenuse of this triangle?

We know a and b here! a=18, b=24.

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The square root of 900 is what will be your answer:

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I hope this helps!

7 0
1 year ago
What is the equation of a circle whose center at (-5, -2) and radius is 2?​
aliya0001 [1]

The equation of a circle whose centre (-5,-2) and radius 2 is x^{2}+y^{2}+10x+4y+25=0

What is equation of a circle?

A circle is a closed curve drawn from a fixed point called centre of the circle. The distance between the centre of the circle and the arc of the circle is called the radius of the circle.

The equation of a circle with centre (h, k) radius r is

(x-h)^{2} +(y-k)^{2}=r^{2}

Given center = (-5,-2)  and Radius = 2

Put the Given value in the equation:

= (x-(-5))^{2} +(y-(-2))^{2} = 2^{2}

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= x^{2} +y^{2}+10x+ 4y+ 29 = 4

= x^{2} +y^{2}+10x +4y+ 29-4=0

= x^{2} +y^{2}+10x+4y+25=0

So, the equation of the circle whose centre is (-5,-2) and Radius 2 is

x^{2}+y^{2}+10x+4y+25=0

To read more about the equation of a circle. you can follow:

brainly.com/question/351704

#SPJ2

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1 year ago
Help!!! One no choices math question! What is the perimeter of the figure shown on the coordinate plane?
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