BUAL 2650 FINAL EXAM QUESTIONS & ANSWERS
Suppose that a random variable x has a uniform distribution with c = 2 and d =8. Find
P(3 <= x <= 5) - Answer -.333
Find the area under the normal curve when P(Z > -2) - Answer -.9772
Find the area under the normal curve between P(1 < z <2) - Answer -.1359
In a manufacturing process, we are interested in measuring 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? -
Answer -601
Rejecting a true null hypothesis is called a ________ error. - Answer -Type 1
A recent study conducted by the state government attempts to determine whether the
voting public supports 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. - Answer -p
≤ .66
In testing H0: μ= 23; versus HA: μ > 23 using the critical value rule, when x¯ = 26, s = 6,
and n = 20, what is the value of the test statistic? Assume that the population from
which the sample is selected is normally distributed. - Answer -2.24
In a manufacturing process, a random sample of 36 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? - Answer -2.228
to 3.772
A confidence interval for the population mean is an interval constructed around the
________. - Answer -sample mean
When the population is normally distributed, population 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. - Answer -the t distribution
The exact spread of the t distribution depends on the ________. - Answer -number of
degrees of freedom
Suppose that a random variable x has a uniform distribution with c = 2 and d =8. Find
P(3 <= x <= 5) - Answer -.333
Find the area under the normal curve when P(Z > -2) - Answer -.9772
Find the area under the normal curve between P(1 < z <2) - Answer -.1359
In a manufacturing process, we are interested in measuring 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? -
Answer -601
Rejecting a true null hypothesis is called a ________ error. - Answer -Type 1
A recent study conducted by the state government attempts to determine whether the
voting public supports 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. - Answer -p
≤ .66
In testing H0: μ= 23; versus HA: μ > 23 using the critical value rule, when x¯ = 26, s = 6,
and n = 20, what is the value of the test statistic? Assume that the population from
which the sample is selected is normally distributed. - Answer -2.24
In a manufacturing process, a random sample of 36 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? - Answer -2.228
to 3.772
A confidence interval for the population mean is an interval constructed around the
________. - Answer -sample mean
When the population is normally distributed, population 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. - Answer -the t distribution
The exact spread of the t distribution depends on the ________. - Answer -number of
degrees of freedom
