BUAL 2650 Final Exam
Study online at https://quizlet.com/_e8n24a
1. Suppose that a random variable x has a uniform distri- .333
bution with c = 2 and d =8. Find P(3 <= x <= 5)
2. Find the area under the normal curve when P(Z > -2) .9772
3. Find the area under the normal curve between P(1 < z .1359
<2)
4. In a manufacturing process, we are interested in mea- 601
suring the average length of a certain type of bolt. Past
data indicate that the standard deviation is .25 inches.
How many manufactured bolts should be sampled in
order to make us 95 percent confident that the sample
mean bolt length is within .02 inches of the true mean
bolt length?
5. Rejecting a true null hypothesis is called a ________ Type 1
error.
6. A recent study conducted by the state government p d.66
attempts to determine whether the voting public sup-
ports a further increase in cigarette taxes. The opinion
poll recently sampled 1,500 voting-age citizens. 1,020
of the sampled citizens were in favor of an increase
in cigarette taxes. The state government would like to
decide if there is enough evidence to establish whether
the proportion of citizens supporting an increase in
cigarette taxes is significantly greater than .66. Identify
the null hypothesis.
7. In testing H0: μ= 23; versus HA: μ > 23 using the critical 2.24
value rule, when x¯ = 26, s = 6, and n = 20, what is the
value of the test statistic? Assume that the population
1/7
, BUAL 2650 Final Exam
Study online at https://quizlet.com/_e8n24a
from which the sample is selected is normally distrib-
uted.
8. In a manufacturing process, a random sample of 36 2.228 to 3.772
manufactured bolts has a mean length of 3 inches
with a standard deviation of .3 inches. What is the 99
percent confidence interval for the true mean length
of the manufactured bolt?
9. A confidence interval for the population mean is an sample mean
interval constructed around the ________.
10. When the population is normally distributed, popula- the t distribution
tion standard deviation σ is unknown, and the sample
size is n = 15, the confidence interval for the population
mean μ is based on the z (normal) distribution.
11. The exact spread of the t distribution depends on the number of degrees of
________. freedom
12. ______ says that if the sample size is sufficiently large, The Central Limit Theorem
then the sample means are approximately normally
distributed.
13. The mean of a standard normal distribution is always 0
equal to ________.
14. ________ values of the standard deviation result in a larger
normal curve that is wider and flatter.
15. The area under the curve of a valid continuous proba- equal 1
bility distribution must ________.
16. uniform
2/7
Study online at https://quizlet.com/_e8n24a
1. Suppose that a random variable x has a uniform distri- .333
bution with c = 2 and d =8. Find P(3 <= x <= 5)
2. Find the area under the normal curve when P(Z > -2) .9772
3. Find the area under the normal curve between P(1 < z .1359
<2)
4. In a manufacturing process, we are interested in mea- 601
suring the average length of a certain type of bolt. Past
data indicate that the standard deviation is .25 inches.
How many manufactured bolts should be sampled in
order to make us 95 percent confident that the sample
mean bolt length is within .02 inches of the true mean
bolt length?
5. Rejecting a true null hypothesis is called a ________ Type 1
error.
6. A recent study conducted by the state government p d.66
attempts to determine whether the voting public sup-
ports a further increase in cigarette taxes. The opinion
poll recently sampled 1,500 voting-age citizens. 1,020
of the sampled citizens were in favor of an increase
in cigarette taxes. The state government would like to
decide if there is enough evidence to establish whether
the proportion of citizens supporting an increase in
cigarette taxes is significantly greater than .66. Identify
the null hypothesis.
7. In testing H0: μ= 23; versus HA: μ > 23 using the critical 2.24
value rule, when x¯ = 26, s = 6, and n = 20, what is the
value of the test statistic? Assume that the population
1/7
, BUAL 2650 Final Exam
Study online at https://quizlet.com/_e8n24a
from which the sample is selected is normally distrib-
uted.
8. In a manufacturing process, a random sample of 36 2.228 to 3.772
manufactured bolts has a mean length of 3 inches
with a standard deviation of .3 inches. What is the 99
percent confidence interval for the true mean length
of the manufactured bolt?
9. A confidence interval for the population mean is an sample mean
interval constructed around the ________.
10. When the population is normally distributed, popula- the t distribution
tion standard deviation σ is unknown, and the sample
size is n = 15, the confidence interval for the population
mean μ is based on the z (normal) distribution.
11. The exact spread of the t distribution depends on the number of degrees of
________. freedom
12. ______ says that if the sample size is sufficiently large, The Central Limit Theorem
then the sample means are approximately normally
distributed.
13. The mean of a standard normal distribution is always 0
equal to ________.
14. ________ values of the standard deviation result in a larger
normal curve that is wider and flatter.
15. The area under the curve of a valid continuous proba- equal 1
bility distribution must ________.
16. uniform
2/7
