TABLE 9-11
An appliance manufacturer claims to have developed a compact microwave oven that
consumes a population mean of no more than 250 W. From previous studies, it is
believed that power consumption for microwave ovens is normally distributed with a
population standard deviation of 15 W. If there is evidence that the population mean
consumption is greater than 250 W, the manufacturer will be unable to make the claim.
Referring to Table 9-11, if you select a sample of 20 compact microwave ovens and are
willing to have a level of significance of 0.01, the power of the test is ________ if the
mean power consumption of all such microwave ovens is in fact 257.3 W.
TABLE 10-4
Two samples each of size 25 are taken from independent populations assumed to be
normally distributed with equal variances. The first sample has a mean of 35.5 and
standard deviation of 3.0 while the second sample has a mean of 33.0 and standard
deviation of 4.0.
Referring to Table 10-4, what is the 99% confidence interval estimate for the difference
in the two means?
TABLE 3-4
The ordered array below represents the number of cargo manifests approved by customs
inspectors of the Port of New York in a sample of 35 days:
16, 17, 18, 18, 19, 20, 20, 21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23, 24, 24, 24, 25, 25,
26, 26, 26, 27, 28, 28, 29, 29, 31, 31, 32, 32
Note: For this sample, the sum of the values is 838, and the sum of the squared
differences between each value and the mean is 619.89.
Referring to Table 3-4, the median of the customs data is ________.
TABLE 11-3
As part of an evaluation program, a sporting goods retailer wanted to compare the
downhill coasting speeds of 4 brands of bicycles. She took 3 of each brand and
determined their maximum downhill speeds. The results are presented in miles per hour
in the table below.
Referring to Table 11-3, the value of MSA is ________, while MSW is ________.
TABLE 7-1
The time spent studying by students in the week before final exams follows a normal
distribution with a standard deviation of 8 hours. A random sample of 4 students was
taken in order to estimate the mean study time for the population of all students.
Referring to Table 7-1, what is the probability that the sample mean differs from the
population mean by more than 3 hours?
TABLE 6-6
According to Investment Digest, the arithmetic mean of the annual return for common
stocks over an 85-year period was 9.5%, but the value of the variance was not
mentioned. Also 25% of the annual returns were below 8%, while 65% of the annual
returns were between 8% and 11.5%. The article claimed that the distribution of annual
return for common stocks was bell-shaped and approximately symmetric. Assume that
this distribution is normal with the mean given above. Answer the following questions
without the help of a calculator, statistical software or statistical table.
Referring to Table 6-6, find the two values that will bound the middle 80% of the
annual returns.
TABLE 7-8
According to a survey, only 15% of customers who visited the website of a major retail
store made a purchase. Random samples of size 50 are selected from a population of
900. Use the finite population correction factor.
Referring to Table 7-8, the standard error of all the sample proportions of customers
who will make a purchase after visiting the website is ________.
A sample that does not provide a good representation of the population from which it
was collected is referred to as a(n) ________ sample.
TABLE 16-5
The number of passengers arriving at San Francisco on the Amtrak cross-country
express on 6 successive Mondays were: 60, 72, 96, 84, 36, and 48.
Referring to Table 16-5, exponentially smooth the number of arrivals using a smoothing
constant of 0.25.