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The amount of time a certain brand of light bulb lasts is normally distributed with a

mean of 2000 hours and a standard deviation of 55 hours. What percentage light bulbs last less than 2080 hours, to the nearest tenth?

Respuesta :

Answer:

92.65 % light bulbs last less than 2080 hours

Step-by-step explanation:

We are given that The amount of time a certain brand of light bulb lasts is normally distributed

Mean =[tex]\mu = 2000[/tex]

Standard deviation =[tex]\sigma = 55[/tex]

We are supposed to find  What percentage light bulbs last less than 2080 hours, to the nearest tenth

[tex]Z = \frac{x-\mu}{\sigma}\\\\Z=\frac{2080-2000}{55}[/tex]

Z=1.45

Refer the z table for p value

p value = 0.9265

Hence 92.65 % light bulbs last less than 2080 hours

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