SCMA 350 QUESTIONS AND ANSWERS
1. As the degrees of freedom increase, the t distribution approaches the _____
distribution. - Answer -normal
2. If the margin of error in an interval estimate of μ is 4.6, the interval estimate equals
_____. - Answer -x bar (x with line over it) +- 4.6
3. The t distribution is a family of similar probability distributions, with each individual
distribution depending on a parameter known as the _____. - Answer -degrees of
freedom
4. The probability that the interval estimation procedure will generate an interval that
contains the actual value of the population parameter being estimated is the _____. -
Answer -confidence coefficient
5. To compute the minimum sample size for an interval estimate of μ when the
population standard deviation is known, we must first determine all of the following
EXCEPT _____. - Answer -degrees of freedom
6. The use of the normal probability distribution as an approximation of the sampling
distribution of is based on the condition that both np and n(1 - p) equal or exceed
_____. - Answer -5
7. The sample size that guarantees all estimates of proportions will meet the margin of
error requirements is computed using a planning value of p equal to _____. - Answer -
.50
8. We can reduce the margin of error in an interval estimate of p by doing any of the
following EXCEPT _____. - Answer -using a planning value p* closer to .5
9. In determining an interval estimate of a population mean when σ is unknown, we use
a t distribution with _____ degrees of freedom. - Answer -n − 1
10. The expression used to compute an interval estimate of μ may depend on any of the
following factors EXCEPT _____. - Answer -whether there is sampling error
11. The mean of the t distribution is _____. - Answer -0
12. An interval estimate is used to estimate _____. - Answer -a population parameter
13. An estimate of a population parameter that provides an interval believed to contain
the value of the parameter is known as the _____. - Answer -interval estimate
14. As the sample size increases, the margin of error _____. - Answer -decreases
, 15. The confidence associated with an interval estimate is called the _____. - Answer -
confidence level
16. The ability of an interval estimate to contain the value of the population parameter is
described by the _____. - Answer -confidence level
17. If an interval estimate is said to be constructed at the 90% confidence level, the
confidence coefficient would be _____. - Answer -.9
18. If we want to provide a 95% confidence interval for the mean of a population, the
confidence coefficient is _____. - Answer -.95
19. For the interval estimation of μ when σ is assumed known, the proper distribution to
use is the_____. - Answer -standard normal distribution
20. The z value for a 97.8% confidence interval estimation is _____. - Answer -2.29
21. It is known that the variance of a population equals 1,936. A random sample of 121
has been selected from the population. There is a .95 probability that the sample mean
will provide a margin of error of _____. - Answer -7.84 or less
22. A random sample of 144 observations has a mean of 20, a median of 21, and a
mode of 22. The population standard deviation is known to equal 4.8. The 95.44%
confidence interval for the population mean is _____. - Answer -19.2 to 20.8
Exhibit 8-1
In order to estimate the average time spent on the computer terminals per student at a
local university, data were collected from a sample of 81 business students over a one-
week period. Assume the population standard deviation is 1.2 hours.
23. Refer to Exhibit 8-1. The standard error of the mean is _____. - Answer -.133
Exhibit 8-1
In order to estimate the average time spent on the computer terminals per student at a
local university, data were collected from a sample of 81 business students over a one-
week period. Assume the population standard deviation is 1.2 hours.
24. Refer to Exhibit 8-1. With a .95 probability, the margin of error is
approximately_____. - Answer -.26
Exhibit 8-1
In order to estimate the average time spent on the computer terminals per student at a
local university, data were collected from a sample of 81 business students over a one-
week period. Assume the population standard deviation is 1.2 hours.
1. As the degrees of freedom increase, the t distribution approaches the _____
distribution. - Answer -normal
2. If the margin of error in an interval estimate of μ is 4.6, the interval estimate equals
_____. - Answer -x bar (x with line over it) +- 4.6
3. The t distribution is a family of similar probability distributions, with each individual
distribution depending on a parameter known as the _____. - Answer -degrees of
freedom
4. The probability that the interval estimation procedure will generate an interval that
contains the actual value of the population parameter being estimated is the _____. -
Answer -confidence coefficient
5. To compute the minimum sample size for an interval estimate of μ when the
population standard deviation is known, we must first determine all of the following
EXCEPT _____. - Answer -degrees of freedom
6. The use of the normal probability distribution as an approximation of the sampling
distribution of is based on the condition that both np and n(1 - p) equal or exceed
_____. - Answer -5
7. The sample size that guarantees all estimates of proportions will meet the margin of
error requirements is computed using a planning value of p equal to _____. - Answer -
.50
8. We can reduce the margin of error in an interval estimate of p by doing any of the
following EXCEPT _____. - Answer -using a planning value p* closer to .5
9. In determining an interval estimate of a population mean when σ is unknown, we use
a t distribution with _____ degrees of freedom. - Answer -n − 1
10. The expression used to compute an interval estimate of μ may depend on any of the
following factors EXCEPT _____. - Answer -whether there is sampling error
11. The mean of the t distribution is _____. - Answer -0
12. An interval estimate is used to estimate _____. - Answer -a population parameter
13. An estimate of a population parameter that provides an interval believed to contain
the value of the parameter is known as the _____. - Answer -interval estimate
14. As the sample size increases, the margin of error _____. - Answer -decreases
, 15. The confidence associated with an interval estimate is called the _____. - Answer -
confidence level
16. The ability of an interval estimate to contain the value of the population parameter is
described by the _____. - Answer -confidence level
17. If an interval estimate is said to be constructed at the 90% confidence level, the
confidence coefficient would be _____. - Answer -.9
18. If we want to provide a 95% confidence interval for the mean of a population, the
confidence coefficient is _____. - Answer -.95
19. For the interval estimation of μ when σ is assumed known, the proper distribution to
use is the_____. - Answer -standard normal distribution
20. The z value for a 97.8% confidence interval estimation is _____. - Answer -2.29
21. It is known that the variance of a population equals 1,936. A random sample of 121
has been selected from the population. There is a .95 probability that the sample mean
will provide a margin of error of _____. - Answer -7.84 or less
22. A random sample of 144 observations has a mean of 20, a median of 21, and a
mode of 22. The population standard deviation is known to equal 4.8. The 95.44%
confidence interval for the population mean is _____. - Answer -19.2 to 20.8
Exhibit 8-1
In order to estimate the average time spent on the computer terminals per student at a
local university, data were collected from a sample of 81 business students over a one-
week period. Assume the population standard deviation is 1.2 hours.
23. Refer to Exhibit 8-1. The standard error of the mean is _____. - Answer -.133
Exhibit 8-1
In order to estimate the average time spent on the computer terminals per student at a
local university, data were collected from a sample of 81 business students over a one-
week period. Assume the population standard deviation is 1.2 hours.
24. Refer to Exhibit 8-1. With a .95 probability, the margin of error is
approximately_____. - Answer -.26
Exhibit 8-1
In order to estimate the average time spent on the computer terminals per student at a
local university, data were collected from a sample of 81 business students over a one-
week period. Assume the population standard deviation is 1.2 hours.
