BANA 2372 Business Analysis/Statistics -
Exam 2 UPDATED ACTUAL Exam
Questions and CORRECT Answers
___ of values of a normal random variable are within +/- 1 standard deviation of the mean. -
CORRECT ANSWER- ✔✔68.26%
___ of values of a normal random variable are within +/- 2 standard deviation of the mean. -
CORRECT ANSWER- ✔✔95.44%
___ of values of a normal random variable are within +/- 3 standard deviation of the mean. -
CORRECT ANSWER- ✔✔99.72%
___ is referred to as the rectangular distribution. - CORRECT ANSWER- ✔✔Uniform
distribution
___is a continuous probability distribution and explains the probability distribution of the
time between random occurrences. - CORRECT ANSWER- ✔✔Exponential probability
distribution
1 /10 10 x f x e , where x 0
The mean of x is ____.
The probability that x is less than 5 is ____. - CORRECT ANSWER- ✔✔10; 0.0606
23% of executives believe an employer has no right to read employee's email. With a sample
size of 1200 construct a 90% confidence interval for the proportion.
Does this sample satisfy the necessary conditions such that the distribution of sample
proportions is approximately normal? - CORRECT ANSWER- ✔✔yes
,A college entrance exam scores the following normal distribution with a mean of 540 and a
standard deviation of 60. About 68% of students taking the exam will score within what
range? - CORRECT ANSWER- ✔✔480 to 600
A continuous probability distribution that is useful in describing the time, or space, between
occurrences of an event is a(n) - CORRECT ANSWER- ✔✔exponential probability
distribution
A continuous random variable can assume any value in an interval on the real line or in a
collection of intervals. - CORRECT ANSWER- ✔✔True
A continuous random variable is uniformly distributed between a and b. The probability
density function between a and b is _____. - CORRECT ANSWER- ✔✔1/(b − a)
A continuous random variable may assume _____. - CORRECT ANSWER- ✔✔all values in
an interval or collection of intervals
A continuous uniform random variable x has a lower bound of a = -3, an upper bound of b =
5. What is p(x > -1)? - CORRECT ANSWER- ✔✔0.7500
A continuous uniform random variable x has a lower bound of a = -21, an upper bound of b =
-6. What value of x provides an area in the upper tail equal to 0.20? - CORRECT ANSWER-
✔✔-9
A health conscious student faithfully wears a device that tracks his steps. Suppose that the
number of steps he takes is normally distributed with a mean of 10,000 and a standard
deviation of 1500 steps. How many steps would he have to take to make the cut for the top
5% for his distribution? - CORRECT ANSWER- ✔✔12,467
A health conscious student faithfully wears a device that tracks his steps. Suppose that the
number of steps he takes is normally distributed with a mean of 10,000 and a standard
deviation of 1500 steps. One day he took 15,000 steps. What was his percentage of steps that
day? - CORRECT ANSWER- ✔✔99.96%
,A health conscious student faithfully wears a device that tracks his steps. Suppose that the
number of steps he takes is normally distributed with a mean of 10,000 and a standard
deviation of 1500 steps. What percent of the time will he exceed 13,000 steps? - CORRECT
ANSWER- ✔✔2.28%
A mean of 0 and a standard deviation of 1 - CORRECT ANSWER- ✔✔minus infinity to
infinity
A negative value of Z indicates that - CORRECT ANSWER- ✔✔the number of standard
deviations of an observation is to the left of the mean
A negative value of z indicates that: - CORRECT ANSWER- ✔✔the number of standard
deviations of an observation is below the mean.
A normal distribution with a mean of 0 and a standard deviation of 1 is called - CORRECT
ANSWER- ✔✔a standard normal distribution
A normal distribution with a mean of zero and a standard deviation of one is called: -
CORRECT ANSWER- ✔✔a standard normal probability distribution.
A normal probability distribution _____. - CORRECT ANSWER- ✔✔is a continuous
probability distribution
A normal probability distribution is____, and its skewness measure is___. - CORRECT
ANSWER- ✔✔symmetric; zero
A numerical measure from a population, such as a population mean, is called _____. -
CORRECT ANSWER- ✔✔a parameter
A professor at a local university noted that the exam grades of her students were normally
distributed with a mean of 73 and a standard deviation of 11.
The professor has informed us that 7.93 percent of her students received grades of A. What is
the minimum score needed to receive a grade of A?
, Students who made 57.93 or lower on the exam failed the course. What percent of students
failed the course?
If 69.5 percent of the students received grades of C or better, what is the minimum score of
those who received C's? - CORRECT ANSWER- ✔✔88.51
8.53%
67.39
A property of the exponential distribution is that the ___ and___ are equal. - CORRECT
ANSWER- ✔✔mean, standard deviation
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 - CORRECT ANSWER- ✔✔19.2
to 20.8
A random variable having a normal distribution with a mean of 0 and a standard deviation of
1. - CORRECT ANSWER- ✔✔standard normal probability distribution
A random variable is ____ whenever the probability is proportional to the interval's length. -
CORRECT ANSWER- ✔✔uniformly distributed
A sample statistic, such as a sample mean, that estimated the value of the corresponding
population parameter is known as a _____________. - CORRECT ANSWER- ✔✔point
estimator
A standard normal distribution is a normal distribution with - CORRECT ANSWER- ✔✔any
mean and any standard deviation
A standard normal distribution is a normal distribution with ____. - CORRECT ANSWER-
✔✔a mean of 0 and a standard deviation of 1
A uniform probability distribution is a continuous probability distribution where the
probability that the random variable assumes a value in any interval of equal length is ___. -
CORRECT ANSWER- ✔✔the same for each interval
Exam 2 UPDATED ACTUAL Exam
Questions and CORRECT Answers
___ of values of a normal random variable are within +/- 1 standard deviation of the mean. -
CORRECT ANSWER- ✔✔68.26%
___ of values of a normal random variable are within +/- 2 standard deviation of the mean. -
CORRECT ANSWER- ✔✔95.44%
___ of values of a normal random variable are within +/- 3 standard deviation of the mean. -
CORRECT ANSWER- ✔✔99.72%
___ is referred to as the rectangular distribution. - CORRECT ANSWER- ✔✔Uniform
distribution
___is a continuous probability distribution and explains the probability distribution of the
time between random occurrences. - CORRECT ANSWER- ✔✔Exponential probability
distribution
1 /10 10 x f x e , where x 0
The mean of x is ____.
The probability that x is less than 5 is ____. - CORRECT ANSWER- ✔✔10; 0.0606
23% of executives believe an employer has no right to read employee's email. With a sample
size of 1200 construct a 90% confidence interval for the proportion.
Does this sample satisfy the necessary conditions such that the distribution of sample
proportions is approximately normal? - CORRECT ANSWER- ✔✔yes
,A college entrance exam scores the following normal distribution with a mean of 540 and a
standard deviation of 60. About 68% of students taking the exam will score within what
range? - CORRECT ANSWER- ✔✔480 to 600
A continuous probability distribution that is useful in describing the time, or space, between
occurrences of an event is a(n) - CORRECT ANSWER- ✔✔exponential probability
distribution
A continuous random variable can assume any value in an interval on the real line or in a
collection of intervals. - CORRECT ANSWER- ✔✔True
A continuous random variable is uniformly distributed between a and b. The probability
density function between a and b is _____. - CORRECT ANSWER- ✔✔1/(b − a)
A continuous random variable may assume _____. - CORRECT ANSWER- ✔✔all values in
an interval or collection of intervals
A continuous uniform random variable x has a lower bound of a = -3, an upper bound of b =
5. What is p(x > -1)? - CORRECT ANSWER- ✔✔0.7500
A continuous uniform random variable x has a lower bound of a = -21, an upper bound of b =
-6. What value of x provides an area in the upper tail equal to 0.20? - CORRECT ANSWER-
✔✔-9
A health conscious student faithfully wears a device that tracks his steps. Suppose that the
number of steps he takes is normally distributed with a mean of 10,000 and a standard
deviation of 1500 steps. How many steps would he have to take to make the cut for the top
5% for his distribution? - CORRECT ANSWER- ✔✔12,467
A health conscious student faithfully wears a device that tracks his steps. Suppose that the
number of steps he takes is normally distributed with a mean of 10,000 and a standard
deviation of 1500 steps. One day he took 15,000 steps. What was his percentage of steps that
day? - CORRECT ANSWER- ✔✔99.96%
,A health conscious student faithfully wears a device that tracks his steps. Suppose that the
number of steps he takes is normally distributed with a mean of 10,000 and a standard
deviation of 1500 steps. What percent of the time will he exceed 13,000 steps? - CORRECT
ANSWER- ✔✔2.28%
A mean of 0 and a standard deviation of 1 - CORRECT ANSWER- ✔✔minus infinity to
infinity
A negative value of Z indicates that - CORRECT ANSWER- ✔✔the number of standard
deviations of an observation is to the left of the mean
A negative value of z indicates that: - CORRECT ANSWER- ✔✔the number of standard
deviations of an observation is below the mean.
A normal distribution with a mean of 0 and a standard deviation of 1 is called - CORRECT
ANSWER- ✔✔a standard normal distribution
A normal distribution with a mean of zero and a standard deviation of one is called: -
CORRECT ANSWER- ✔✔a standard normal probability distribution.
A normal probability distribution _____. - CORRECT ANSWER- ✔✔is a continuous
probability distribution
A normal probability distribution is____, and its skewness measure is___. - CORRECT
ANSWER- ✔✔symmetric; zero
A numerical measure from a population, such as a population mean, is called _____. -
CORRECT ANSWER- ✔✔a parameter
A professor at a local university noted that the exam grades of her students were normally
distributed with a mean of 73 and a standard deviation of 11.
The professor has informed us that 7.93 percent of her students received grades of A. What is
the minimum score needed to receive a grade of A?
, Students who made 57.93 or lower on the exam failed the course. What percent of students
failed the course?
If 69.5 percent of the students received grades of C or better, what is the minimum score of
those who received C's? - CORRECT ANSWER- ✔✔88.51
8.53%
67.39
A property of the exponential distribution is that the ___ and___ are equal. - CORRECT
ANSWER- ✔✔mean, standard deviation
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 - CORRECT ANSWER- ✔✔19.2
to 20.8
A random variable having a normal distribution with a mean of 0 and a standard deviation of
1. - CORRECT ANSWER- ✔✔standard normal probability distribution
A random variable is ____ whenever the probability is proportional to the interval's length. -
CORRECT ANSWER- ✔✔uniformly distributed
A sample statistic, such as a sample mean, that estimated the value of the corresponding
population parameter is known as a _____________. - CORRECT ANSWER- ✔✔point
estimator
A standard normal distribution is a normal distribution with - CORRECT ANSWER- ✔✔any
mean and any standard deviation
A standard normal distribution is a normal distribution with ____. - CORRECT ANSWER-
✔✔a mean of 0 and a standard deviation of 1
A uniform probability distribution is a continuous probability distribution where the
probability that the random variable assumes a value in any interval of equal length is ___. -
CORRECT ANSWER- ✔✔the same for each interval
