Question

Suppose that a certain brand of light bulb has a mean life of 450 hours and a standard deviation of 73 hours. Assuming the data are bell-shaped: (Show work to get full credit)

a. Would it be unusual for a light bulb to have a life span of 320 hours? 615 hours? Justify each response.

b. According to the Empirical Rule, 99.7% of the light bulbs have a lifetime between what two values?

c. Determine the percentage of light bulbs that will have a life between 304 and 596 hours.

Answer #1

Hit like please.

Let X denote the lifetime of a light bulb of a certain brand.
Suppose that the lifetime of a light bulb of this particular brand
has an exponential distribution with mean lifetime of 200 hours.
What is the probability that a light bulb has a lifetime between
100 and 400 hours?

The lifetime of a certain brand of electric light bulb is known
to have a standard deviation of 53 hours. Suppose that a random
sample of 100 bulbs of this brand has a mean lifetime of 481 hours.
Find a 99% confidence interval for the true mean lifetime of all
light bulbs of this brand. Then complete the table below. Carry
your intermediate computations to at least three decimal places.
Round your answers to one decimal place. (If necessary, consult...

The lifetime of a certain brand of electric light bulb is known
to have a standard deviation of
51
hours. Suppose that a random sample of
150
bulbs of this brand has a mean lifetime of
481
hours. Find a
90%
confidence interval for the true mean lifetime of all light
bulbs of this brand. Then complete the table below.
Carry your intermediate computations to at least three decimal
places. Round your answers to one decimal place. (If necessary,
consult...

a light bulb manufacturer guarantees that the mean
life of a certain type of light bulb is at least 762 hours.A random
sample of 20 light bulbs has a mean life of 736 hours. assume the
population. is normally distributed and the population standard
deviation is 65 hours. at a=0.08

The mean life of a certain brand of auto batteries is 51 months
with a standard deviation of 6 months. Assume that the lives of all
auto batteries of this brand have a bell-shaped distribution. Using
the empirical rule, find the percentage of auto batteries of this
brand that have a life of
a. 33 to 69 months: %
b. 45 to 57 months: %

A new extended-life light bulb has an average life of 750 hours,
with a standard deviation of 50 hours. If the life of these light
bulbs approximates a normal distribution, about what percent of the
distribution will be between 650 hours and 850 hours?
Seleccione una:
A. 95%
B. 68%
C. 99%
D. 34%

For a random sample of 10 light bulbs, the mean bulb life is
4,000 hr with a sample standard deviation 200. For another brand of
bulbs, a random sample of 8 has a sample mean of 4,300 hr and a
sample standard deviation of 250. Assume that the life of a light
bulb is normally distributed and the standard deviations of the two
populations are equal. We test the hypothesis that there is no
difference between the mean operating life...

Problem 7
Suppose you have a random variable X that represents the
lifetime of a certain brand of light bulbs. Assume that the
lifetime of light bulbs are approximately normally distributed with
mean 1400 and standard deviation 200 (in other words X ~ N(1400,
2002)).
Answer the following using the standard normal distribution
table:
Approximate the probability of a light bulb lasting less than
1250 hours.
Approximate the probability that a light bulb lasts between 1360
to 1460 hours.
Approximate...

If light bulbs have lives that are normally distributed with a
mean of 2500 hours and a standard deviation of 500 hours, use the
68-95-99.7 rule to approximate the percentage of light bulbs having
a life less than 1500

Suppose a brand of light bulbs is normally distributed, with a
mean life of 1400 hr and a standard deviation of 50 hr.Find the
probability that a light bulb of that brand lasts between 1315 hr
and 1460 hr.
Areas Under the Standard Normal Curve
z
A
z
A
1.00
.3413
1.50
.4332
1.10
.3643
1.60
.4452
1.20
.3849
1.70
.4554
1.30
.4032
1.80
.4641
1.40
.4192
1.90
.4713
The probability that a light bulb will last between 1315 hr...

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