Question

The life expectancy of vacuum cleaner is normally distributed with a mean of 48 months and a standard deviation of 12 months. 90% of the vacuum cleaners will have a life expectancy of at least how many months?

(a)28.3 (b)32.6 (c)46.4 (d)67.7 (e)49.6

Answer #1

answer is 32.6

1.
Suppose the lifetimes of Hoover vacuum cleaners are normally
distributed with an average life (μ) of 12 years and a population
standard deviation (σ) of 1.4 years.
What proportion of Hoover vacuum cleaners will last 14 years
or more?
2. Suppose the lifetimes of Hoover vacuum cleaners are
normally distributed with an average life (μ) of 12 years and a
population standard deviation (σ) of 1.4 years.
Calculate the 80th percentile.
3. Suppose the lifetimes of Hoover vacuum cleaners...

Suppose that the duration of trouble-free operation of a new
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The standard error of the sample mean is__days.
The probability that the average duration of trouble-free
operation time is between 480 days and 530 days is _____ (4
decimals place)

Suppose that the duration of trouble-free operation of a new
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the duration (in days) of trouble-free operation. Which of the
following is NOT TRUE for the
sample average of number of trouble-free operation days
()?
P (x̄ < 500) = P(Z < -2.5)
P (x̄ > 600) =...

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Tires that wear out by _____________ miles will be replaced free
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From experience, it is known that the life expectancy of tires
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the average life expectancy for US women is approximately
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What is the z-score for a women how lived to the age of
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What precent age of US women...

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