STATS FINAL EXAM (CH 6-9) QUESTIONS AND ANSWERS FULLY SOLVED
a.
categorical
b.
qualitative
c.
discrete
d.
continuous
ANS: D - Answers A random variable that assume any value from an interval (or collection of intervals) is
called
a.
The annual incomes of American households
b.
The heights of UT undergraduate students
c.
The time of a flight between Toledo Express and Chicago O'Hare
d.
The number of arrivals to a bank in a two hour period
ANS: D - Answers Which of the following random variables is not continuous (is discrete)?
a.
normal function
b.
uniform function
,c.
probability mass function
d.
probability density function
ANS: D - Answers The function that defines the probability distribution of a continuous random variable
is a
a.
The probability that it assumes a particular value is zero
b.
Its density function is constant for any value from [a,b]
c.
For all subintervals of [a,b] with equal length, the probability of taking a value from the subinterval is the
same.
d.
all of the above
ANS: D - Answers A continuous random variable with the uniform distribution on an interval [a,b]
satisfies the following
a.
The mean, median, and mode are equal, and they can be negative, zero, or positive.
b.
A larger value of the standard deviation results in a normal curve (normal density function) that is flatter
around the mean.
c.
A normal curve (normal density function) is bell-shaped and the area under the curve is 1.
d.
, Theoretically, the possible values are from minus infinity to infinity
e.
Both tails of a normal curve (normal density function) are asymptotical in the sense that they approach
the horizontal axis and touch it.
ANS: E - Answers Which of the following is not a characteristic of normal distributions?
a.
a probability density function
b.
an ordinary normal curve
c.
the standard normal distribution (the zdistribution)
d.
none of these alternatives is correct
ANS: C - Answers A normal distribution with a mean of 0 and a standard deviation of 1 is called
a.
z = (x - μ)σ
b.
z = (x - μ)/σ
c.
z = μ + xσ
d.
z = (μ - x)/σ
a.
categorical
b.
qualitative
c.
discrete
d.
continuous
ANS: D - Answers A random variable that assume any value from an interval (or collection of intervals) is
called
a.
The annual incomes of American households
b.
The heights of UT undergraduate students
c.
The time of a flight between Toledo Express and Chicago O'Hare
d.
The number of arrivals to a bank in a two hour period
ANS: D - Answers Which of the following random variables is not continuous (is discrete)?
a.
normal function
b.
uniform function
,c.
probability mass function
d.
probability density function
ANS: D - Answers The function that defines the probability distribution of a continuous random variable
is a
a.
The probability that it assumes a particular value is zero
b.
Its density function is constant for any value from [a,b]
c.
For all subintervals of [a,b] with equal length, the probability of taking a value from the subinterval is the
same.
d.
all of the above
ANS: D - Answers A continuous random variable with the uniform distribution on an interval [a,b]
satisfies the following
a.
The mean, median, and mode are equal, and they can be negative, zero, or positive.
b.
A larger value of the standard deviation results in a normal curve (normal density function) that is flatter
around the mean.
c.
A normal curve (normal density function) is bell-shaped and the area under the curve is 1.
d.
, Theoretically, the possible values are from minus infinity to infinity
e.
Both tails of a normal curve (normal density function) are asymptotical in the sense that they approach
the horizontal axis and touch it.
ANS: E - Answers Which of the following is not a characteristic of normal distributions?
a.
a probability density function
b.
an ordinary normal curve
c.
the standard normal distribution (the zdistribution)
d.
none of these alternatives is correct
ANS: C - Answers A normal distribution with a mean of 0 and a standard deviation of 1 is called
a.
z = (x - μ)σ
b.
z = (x - μ)/σ
c.
z = μ + xσ
d.
z = (μ - x)/σ
