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Paul [167]
3 years ago
9

Quality control is an important issue at ACME Company which manufacturers light bulbs. In order to conduct testing of the life h

ours of their light bulbs, they randomly sampled nine light bulbs and measured how many hours they lasted: 378, 361, 350, 375, 200, 391, 375, 368, and 321. What is the Variance?
Mathematics
1 answer:
mrs_skeptik [129]3 years ago
4 0

Answer: 3424.28

Step-by-step explanation:

Given data : 378, 361, 350, 375, 200, 391, 375, 368,  321

Number of data values = 9

Mean :\overline{x}=\dfrac{\sum^n_{i=1} x_i}{n}

\\\\=\dfrac{378+361+350+375+200+391+375+368+321}{9}\\\\=\dfrac{3119}{9}\approx346.56

Variance = \dfrac{\sum^n_{i=1} (x_i-\overline{x})^2}{n-1}

\sum^n_{i=1} (x_i-\overline{x})^2 = (31.44)^2+(14.44)^2+(3.44)^2+(28.44)^2+(-146.56)^2+(44.44)^2+(28.44)^2+(21.44)^2+(-25.56)^2\\\\=27394.2224

Variance = \dfrac{27394.2224}{8}=3424.2775\approx3424.28

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I need help ASAP I’ll give brainliest to that person :)
guajiro [1.7K]

Volume of sphere = 4/3 x pi x r^3

904.32 = 4/3 x pi x r^3

Divide both sides by 4/3

678.4 = pi x r^3

Divide both sides by pi:

216 = r^3

Take the cubic root of both sides

R = 6

6 0
3 years ago
Order the side from greatest to least.<br> Η.<br> 28°<br> 118°<br> K<br> J<br> side [Select ]
KIM [24]

Answer:

HJ>KJ>HK

Step-by-step explanation:

Side opposite to the largest angle is the largest.

Side opposite to smallest angle is the smallest.

ang K = 118° ang J = 28°

ang K + ang J + ang H = 180° (Sum of all the angles in the triangle is 180°)

118°+28°+angH=180° (Putting the values of ang K & ang J)

146°+angH=180°

ang H=180°-146°

ang H=34°

128°>34°>28°

ang K>ang H>ang J

Here, ang K is the largest, so the side opposite to it i.e. HJ will be the largest side.

Smaller than ang K and bigger than ang J is ang H, so the side opposite to it i.e. KJ will be smaller than HJ but bigger than HK.

Ang J is the smallest angle, so the side opposite to it i.e. HK will be the smallest.

HJ>KJ>HK.

4 0
3 years ago
What is the vertex of the parabola whose equation is y = (x + 1)2 + 3? (-1, -3) (-1, 3) (1, 3)
White raven [17]
Algebra:
A standard parabola is y = x^2. Its vertex is at (0,0)
You can change the position (or vertex) of the parabola.
To move a parabola across the x-axis, you can add or subtract a number from x WITHIN brackets of the ^2
eg. (x + 1)^2 will move the parabola across the x-axis. It will move is one unit to the LEFT (as the sign is opposite to the direction it moves ie. The sign it + but you move the whole parabola in the -ve direction).
Adding or subtracting a number from x OUTSIDE of the ^2 moves the parabola up or down the y-axis
eg. x^2 + 3 will move the parabola UP 3 units (the sign is the same as the direction it moves when the added/subtracted number is outside of the ^2 ie. the sign is positive so the parabola moves up in the positive direction)

From this, we can conclude that because (x + 1)^2 + 3, the vertex will be where x = -1 and where y = 3

Vertex : (-1,3)



Calculus:
f(x) = (x + 1)^2 + 3 = x^2 + 2x + 1 + 3 = x^2 + 2x + 4
Expanding the formular to make it easier to differentiate

f'(x) = 2x + 2
Differentiating (finding the formular the the gradiet of the parabola)

0 = 2x + 2
When the gradient is equal to zero, it must be the vertex

-2 = 2x
-2/2 = x
x = -1
Solve to give the x value at the vertex

f(x) = (x + 1)^2 + 3
= (-1 + 1)^2 + 3
Substitute x = -1 into original equatiom to find y value at the vertex

= (0)^2 + 3
= 0 + 3
= 3
Solve for y

Vertex : (-1,3)


6 0
3 years ago
A restaurant stacked 7 pieces of wood on top of one another if each piece was 4/8 of a foot tall how tall was his pile
Contact [7]
His pile was 3 1/2 ft
Hope this helps!
7 0
3 years ago
What is X? How do you know?
natka813 [3]
The sides of a right triangle are related by trig functions of the acute angles. The relationships are described by the mnemonic SOH CAH TOA. The meaning of this is
.. Sin = Opposite/Hypotenuse
.. Cos = Adjacent/Hypotenuse
.. Tan = Opposite/Adjacent

Here, you are given the adjacent side and the hypotenuse for the angle. This means you can use the relation
.. Cos = Adjacent/Hypotenuse

Putting in the given information lets you find x.
.. cos(22°) = x/11
.. 11*cos(22°) = x ≈ 10.199
8 0
3 years ago
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