A major videocassette rental chain is considering opening a new store in an area that
currently does not have any such stores. The chain will open if there is evidence that
more than 2,000 of the 10,000 households in the area are equipped with videocassette
recorders (VCRs). The marketing manager will conduct a telephone poll of 400
randomly selected households in the area. Using a 5% level of significance, the error
range is
10%
4.9%
3.9%
2.9%
2%
Following question 1, the marketing manager conducts a telephone poll of 400
randomly selected households in the area and finds that 92 have VCRs. The rental
chain’s conclusion from the hypothesis test using a 5% level of significance is:
to open a new store.
not to open a new store.
to delay opening a new store until additional evidence is collected.
we cannot tell what the decision should be from the information given.
None of the above.
Which of the following statements is correct?
The null hypothesis is there is no occupancy difference among the 5 locations. The
analysis of variance is as the following table. The conclusion is to reject the null
hypothesis.
The null hypothesis is there is no occupancy difference among the 5 locations. The
analysis of variance is as the following table. The conclusion is not to reject the null
hypothesis.
The null hypothesis is there is no occupancy difference among the 5 locations. The
analysis of variance is as the following table. The conclusion is to reject the null
hypothesis.
The null hypothesis is there is no occupancy difference among the 5 locations. The
analysis of variance is as the following table. The conclusion is not to reject the null
hypothesis.
The null hypothesis is there is no occupancy difference among the 5 locations.
Because the means of five locations shown in the following table are different, the
conclusion is to reject the null hypothesis.
The professor wanted to find out the average amount of time per week her students
spend studying for the class. Among the 82 students in her class, 30% were freshmen,
45% were sophomores and 25% were juniors. She decided to draw 6 students
randomly from the freshmen, 9 randomly from the sophomores and 5 randomly from
the juniors. This is an example of
a systematic sample
a complete random sample
a stratified sample.
a snowball sample.
a convenience sample.
Suppose a 95% confidence interval for μ turns out to be (56.7, 86.2). To make more
useful inferences from the data, it is desired to reduce the width of the confidence
interval. Which of the following will result in a reduced interval width?
Enlarge the sample frame.
Adopt the completely random sampling method.
Decrease the type II error and increase the type I error.
Increase the confidence level and enlarge the sample size.
Decrease the confidence level and increase the sample size.
Six experts rated two brands of Wulong tea in a taste-testing experiment. A rating on a
7-point scale (1 = extremely unpleasing, 7 = extremely pleasing) is given for each of
four characteristics: taste, aroma, richness, and acidity. The following data displays the
summated ratings-accumulated over all four characteristics. It is believed that the
ratings follow normal distribution. To test whether two brands have different tastes,
which of the following is correct?
The information is insufficient to decide.
.
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