Question

Last year, the mean running time for a certain type of flashlight
battery was 8.5 hours. This year, the manufacturer has introduced a
change in the production method which he hopes will increase the
mean running time. A random sample of 40 of the new light bulbs was
obtained and the mean running time was found to be 8.7 hours. Do
the data provide sufficient evidence to conclude that the mean
running time of the new light bulbs is larger than last year mean
of 8.5 hours? Perform the hypothesis test using a significance
level of 5%. Assume that population standard deviation is 0.5
hours. What is your conclusion?

Answer #1

In the past, the mean running time for a certain type
of flashlight battery has been 8.1 hours. The manufacturer has
introduced a change in tge production method and wants to perform a
hypothesis test to determine whether the mean running time has
increased as a result. the hypotheses are below. Identify tge Type
1 error.
Ho: mean = 8.1 hours
Ha: mean > 8.1 hours

Lightbulbs of a certain type are advertised as having an average
lifetime of 750 hours. The price of these bulbs is very favorable,
so a potential customer has decided to go ahead with a purchase
arrangement unless it can be conclusively demonstrated that the
true average lifetime is smaller than what is advertised. A random
sample of 40 bulbs was selected, the lifetime of each bulb
determined, and the appropriate hypotheses were tested using
MINITAB, resulting in the accompanying output....

A battery manufacturer advertises that the mean reserve capacity
of a certain battery is 1500 hours. You suspect that the batteries’
reserve time is less than the advertised value. To test this claim,
you randomly select a sample of 20 batteries and find the mean
reserve capacity to be 1320 hours. Assume that the population
standard deviation is 320 hours. Do you have enough evidence to
support the manufacturer’s claim? What assumption is necessary for
this test to be valid?...

Lightbulbs of a certain type are advertised as having an average
lifetime of 750 hours. The price of these bulbs is very favorable,
so a potential customer has decided to go ahead with a purchase
arrangement unless it can be conclusively demonstrated that the
true average lifetime is smaller than what is advertised. A random
sample of 44bulbs was selected, the lifetime of each bulb
determined, and the appropriate hypotheses were tested using
MINITAB, resulting in the accompanying output.
Variable...

In the past, the mean lifetime of a certain type of
radio battery has been 9.8 hours. The manufacturer has introduced a
change in the production method and wants to perform a significance
test to determine whether the mean lifetime has increased as a
result. The hypotheses are:
H0: μ = 9.8 hours Ha: μ > 9.8 hours Explain the
meaning of a Type I error.
A) Concluding that μ > 9.8 hours when in fact μ = 9.8
hours...

A certain type of battery produced by Omni Consumer Products has
historically had an average lifespan of no more than 87 hours. Omni
believes that an improved production process will be able to
increase the lifespan of this battery, but it needs to do some
testing before it can conclude anything. Researchers gathered a
sample of 36 batteries and found the sample mean lifespan was 88.5
hours, with a standard deviation of 9.1 hours
Perform a hypothesis test at the...

To test whether the mean time needed to mix a batch of material
is the same for machines produced by three manufacturers, a
chemical company obtained the following data on the time (in
minutes) needed to mix the material.
Manufacturer
1
2
3
19
29
21
25
27
19
24
32
23
28
28
25
(a)
Use these data to test whether the population mean times for
mixing a batch of material differ for the three manufacturers.
Use
α =...

Last year a fast food restaurant had a mean service time of 155
seconds. This year the manager wants to determine whether the
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customers is selected and the sample mean service time = 151
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seconds.
(a) What is the population? What is the sample?
(b) Ata = 0.1 level of significance, determine whether there
is evidence that the population mean...

1. You want to do a study to determine the mean amount
of time, in hours, an SMC student spends at a paid job each week.
Initial studies indicate that there is a standard deviation of 4.6
hours. The result should be found to 95% confidence to within 0.5
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a. 18 students
b. 30 students
c. 19 students
d. 326 students
e. 325 students
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The mean length of time required to perform a certain assembly
line task at Joe’s Manufacturing has been established to be 15.5
minutes, with a standard deviation of 3 minutes. A random sample of
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average time these 9 employees take to perform the same task is
13.5 minutes. The plant manager would like to be at least 98% sure
before switching any more employees to the new, perhaps...

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