Question

The lifetime of a certain type of battery is known to be normally distributed with a population standard deviation of 20 hours. A sample of 50 batteries had a mean lifetime of 120.1 hours.

a. What is the point estimate?

b. Calculate the sampling error.

c. Construct a 95% confidence interval for the population mean. Explain the answer in a sentence.

Answer #1

Confidence interval calculation.

Here Z confidence interval calculation because population standard deviation is known.

The lifetime of a certain type of battery is normally
distributed with mean value 13 hours and standard deviation 1 hour.
There are nine batteries in a package. What lifetime value is such
that the total lifetime of all batteries in a package exceeds that
value for only 5% of all packages? (Round your answer to two
decimal places.)
hours

The lifetime of a certain type of battery is normally
distributed with mean value 11 hours and standard deviation 1 hour.
There are nine batteries in a package. What lifetime value is such
that the total lifetime of all batteries in a package exceeds that
value for only 5% of all packages? (Round your answer to two
decimal places.)
hours

The lifetime of a certain type of battery is normally
distributed with mean value 11 hours and standard deviation 1 hour.
There are four batteries in a package. What lifetime value is such
that the total lifetime of all batteries in a package exceeds that
value for only 5% of all packages? (Round your answer to two
decimal places.)

The lifetime of a certain type of battery is normally
distributed with a mean of 1000 hours and a standard deviation of
100 hours. Find the probability that a randomly selected battery
will last between 950 and 1050 hours

The lifetime of a certain brand of battery is known to have a
standard deviation of 16 hours. Suppose that a random sample of 50
such batteries has a mean lifetime of 37.6 hours. Based on this
sample, find a 90% confidence interval for the true mean lifetime
of all batteries 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...

It is known that the lifetime of a certain type of light bulb is
normally distributed with
a mean lifetime of 1,060 hours and a standard deviation of 125
hours. What is the
probability that a randomly selected light bulb will last
between 1,000 and 1,100 hours?

The average lifetime of batteries of a particular brand are
known to be normally distributed with a standard deviation 8 hours.
How large a sample size would be required to estimate the average
lifetime within 2 hours with a 95% confidence?
If you get a decimal in your answer, always round it up
for the sample size.

9. The standard deviation of the lifetime of a certain type of
lightbulb is known to equal 100 hours. A sample of 169 such bulbs
had an average life of 1350 hours. Find a
(a) 90percent (b) 95percent (c) 99percent
confidence interval estimate of the mean life of this type of
bulb.

The life in hours of a battery is known to be approximately
normally distributed with standard deviation σ = 1.5 hours. A
random sample of 10 batteries has a mean life of ¯x = 50.5 hours.
You want to test H0 : µ = 50 versus Ha : µ 6= 50.
(a) Find the test statistic and P-value.
(b) Can we reject the null hypothesis at the level α = 0.05?
(c) Compute a two-sided 95% confidence interval for the...

The lifetime of a certain kind of battery is exponentially
distributed, with an average lifetime of 25 hours. 12. Draw a graph
to represent the probability that the average lifetime of 16
batteries is between 20 and 25 hours. Shade an appropriate region.
(See Question 8) Question #8 says: Find the probability that the
average lifetime of 16 batteries is between 20 and 25 hours.

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 28 minutes ago

asked 37 minutes ago

asked 52 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago