Question

We are interested in determining whether the variances of the sales at two music stores (A and B) are equal. A sample of 25 days of sales at store A has a sample standard deviation of 30, while a sample of 16 days of sales from store B has a sample standard deviation of 20. At 95% confidence, the null hypothesis _____. a. should be rejected b. should not be rejected c. should be revised d. None of these answers are correct.

Answer #1

Ans:

a. should be rejected

A grocery store is interested in determining whether or
not a difference exists between the shelf life of two different
brands of doughnuts. A random sample of 100 boxes of each brand was
selected and the shelf life in days was determined for each box.
The sample results are given below.
Brand A
Brand B
mean = 2.1
mean = 2.9
standard deviation = 0.8
standard deviation = 1.7
sample size = 100
sample size = 100
Find a 90%...

In order to determine whether or not there is a significant
difference between the mean hourly wages paid by two companies (of
the same industry), the following data have been accumulated.
Company A
Company B
Sample size
80
60
Sample mean
$16.75
$16.25
Population standard deviation
$1.00
$.95
At the 5% level of significance, the null hypothesis
a.
should be rejected.
b.
should not be rejected.
c.
should be revised.
d.
should not be tested.

The researcher is interested in determining whether there is
evidence that the two processes yield different average errors. The
population standard deviations are unknown but are assumed equal.
What is the null hypothesis?
A. H0: µA = µB
B. H0: µA ¹ µB
C. H0: µA £ µB
D. H0: µA > µB

The CEO of Kohl’s is interested in understanding whether the
average store sales for the stores in the east coast are
significantly different from those in the west coast. The CEO
suspects that since the company has been advertising more in the
east coast, the east coast sales would be higher than those in the
west coast. In order to test his hypothesis, the CEO asks his
secretary to randomly pick 10 stores each in the east and west
coasts...

For your answers pick one
*A researcher was interested in inspecting the effect of
classical music on stress among New York students. She studied a
sample of 30 New York students. She found that z= -3.00. Using a =
0.5(two-tailed), what can she conclude?
-Reject the null hypothesis and conclude that classical music
has no effect on stress levels
-Reject the null hypothesis and conclude that classical music has
no effect on stress levels
-Failed to reject the null hypothesis...

A manufacturer is interested in the output voltage of a power
supply used is a PC. Output voltage is assumed to be normally
distributed with standard deviation 0.25 Volts, and the
manufacturer wishes to test H0: μ = 5 Volts against
Ha: μ≠ 5 Volts, using n = 8 units at 5% significance
level. If the sample mean is 5.10, then the corresponding p-value
is
0.295
0.258
0.05
1.13
) In testing the hypotheses H0: μ = 200 vs.
Ha:...

A botanist is interested in determining the average diameter of
the flowers of
a particular plant. She decided to take a random sample of size 80
of these
flowers and found that the sample mean of the flower diameters was
9.6 cm,
and the sample standard deviation was 2.2 cm.
(a) Calculate the value of the estimated standard error of the
sample mean.
(b) Calculate a 95% confidence interval for the population mean of
the
flower diameter of this particular...

The quality control department has collected data on defective
products produced over a 24 hours time span. Using a random sample
of 1500 products, they discover that the average number of defects
is 254, while the sample standard deviation is 20. The department
wants to conduct a test of whether the average number of defective
product is equal to 252 or not.
Which of the following is true?
a.
The Null Hypothesis can be rejected with 95% confidence.
b.
The...

A researcher is interested in determining the average number of
years new teachers remain in the classroom. If past information
shows a standard deviation of 5 years, what size sample should be
taken so that at 95% confidence the margin of error will be 6
months or less?
a. 3
b. 385
c. 2
d. 384

2. We are interested in determining whether the diving depth of
sea otters depends on
whether the animal has eaten, and we predict that diving depth
will be lower after it eats than
before. We attach time depth recorders to 50 otters and watch
them forage. Only two
observations of diving are made per otter -- one before it eats,
then one after —and we realize
after collecting the data that there is considerable variation
among otters in diving behavior....

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 49 seconds ago

asked 15 minutes ago

asked 17 minutes ago

asked 18 minutes ago

asked 20 minutes ago

asked 20 minutes ago

asked 23 minutes ago

asked 25 minutes ago

asked 25 minutes ago

asked 42 minutes ago

asked 52 minutes ago

asked 1 hour ago