QNT 561 Week 2 Quiz

QNT 561 Week 2 Quiz

1. The probability distribution shown here
describes a population of measurements that can assume values of 1, 2, 3, and
4, each of which occurs with the same relative frequency.
x p(x)
1 0.25
2 0.25
3 0.25
4 0.25
a. Calculate
the mean of all the different samples of n=2 measurements that can be selected
from this population. Select the correct choice below.
b.
If a sample of n=2 measurements is randomly selected from the
population, what is the probability that a specific sample will be selected?
c. Complete the sampling
distribution table.
Construct
a probability histogram for the sampling distribution of x.

2.
Suppose a random sample of n=64 measurements is selected from a population with
a mean ? and standard deviation ?. For each of the following values of ? and ?
give the values of ?- and ?-
a.
?=8 ?=2;
b.
?=64 ?=64;
c.
?=16 ?=56;
d. ?=8
?=152;

3. A random sample of n=100
observations is selected from a population with ? =30 and ?=22. Approximate the
probabilities shown below.
a. P(x?28);
b. P(22.1?x?26.8)
c.
P(x?28.2)
d. P(x?27.0)

4. A random sample of 93
observations produced a mean x=26.2 and a standard deviation s=2.4.
a. Find a 95% confidence interval
for ?.
b. The 90% confidence interval for
?.
c. The 99% confidence interval for
?.

5. The random sample shown
below was selected from a normal distribution.
10,3,4,7,4,8
a. Construct a 95% confidence
interval for the population mean ?.
b. Assume that sample mean x and
sample standard deviation remain exactly the same as those you just
calculated but they are based on the sample of n=25 observations. Repeat
part a. What is the effect of increasing the sample size on the width of the
confidence interval?

6. For the binomial sample
information summarized below indicate whether the sample size is
large enough to use the large sample approximation to construct a
confidence interval for p.
n=40, p=0.25
Is the sample size large enough?

7. A newspaper reported that 50% of
people say that some coffee shops are overpriced. The source of this
information was a telephone survey of 40 adults.
a. Identify the population of
interest.
b. Identify the sample.
c. Identify the parameter of
interest.
d. The 90% confidence interval
for the parameter of interest
Question
8: If you wish to estimate a
population mean with a sampling distribution error SE=0.29 using a 95%
confidence interval and you know from prior sampling that ?^2 is approximately
equal to 4.1 how many observations would have to be included in your
sample?

9. Suppose N=5,000, n=1,000, and
s=50.
a. What is the standard error of x?
b. What is the standard error of x
if n=2,000?
c. What is the standard error of x
if n=5,000?
d. What happens to the standard
error of x as n is increased?

10.
Suppose you want to estimate a population proportion , p, and p^=0.33 and
N=6,100, and n=1,400. Find an approximate 95% confidence interval for p.

11. What is specifically observed or
what participants are asked in research study?

12. Data which someone has at least
interpreted once since the event has occurred and has been recorded.

13. When a business decision is
required in response to a problem or opportunity this is called.

14. Which characteristic of good
research involves distinguishing between the organization’s symptoms, its
problems, the manager’s perception of the problems, and the research
problem?

15. Which of the following types of
research is conducted to answer the questions who, what, where, and sometimes
how?

16. This type of study is loosely
structured and designed to understand future research requirements.

17. A firm is conducting a research
study trying to ascertain if customers are sensitive to price changes on its
products. This is an example of.