BUAL 2650 FINAL EXAM (GUPTA AU) | QUESTIONS
AND ANSWERS | SCORED A+
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
______ says that if the sample size is sufficiently large, then the sample means
are approximately normally distributed. Answer - The Central Limit Theorem
The mean of a standard normal distribution is always equal to ________.
Answer - 0
________ values of the standard deviation result in a normal curve that is
wider and flatter. Answer - larger
AND ANSWERS | SCORED A+
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
______ says that if the sample size is sufficiently large, then the sample means
are approximately normally distributed. Answer - The Central Limit Theorem
The mean of a standard normal distribution is always equal to ________.
Answer - 0
________ values of the standard deviation result in a normal curve that is
wider and flatter. Answer - larger
