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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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The mass of an ornament is m grams.
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Given:

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m is directly proportional to the cube of h.

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Where, k is the constant of proportionality.

Putting m = 525 and h= 5, we get

525=k(5)

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Justin builds a triangular fenced area for his dog called Triangle ABC. If AB = 17 ft and BC = 8ft, and angle C is a right angle
Anika [276]

The missing side of the fence measures 15 ft

The perimeter of the fence is 40 ft

The area inside the fenced in section is 60 ft²

The fence is triangular and a right triangle.

<h3>Right triangle:</h3>

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