ECN 221 ASU Exam 2 Review
Questions with complete solution
2025
*normal distribution*
Converting to z-scores - correct answer Subtracting the mean and dividing it
by the standard deviation
*normal distribution*
To find the probability of a value being less than or equal to x... - correct
answer 1. Convert X to a z value by subtracting mean and dividing by the
standard deviation
2. Then put in excel as =NORM.S.DIST(z,true)
*normal distribution*
To find the z-value in excel you use the excel function... - correct answer
=NORM.S.INV(probability)
This is the backwards way of finding the probability of a value being less than
or equal to x
There are two types of continuous distribution.... - correct answer Normal and
Uniform
normal distribution is.... - correct answer A function that represents the
distribution of variables as a symmetrical bell-shaped graph.
uniform distribution is... - correct answer the frequency of each value of the
variable is evenly spread out across the values of the variable
,ex: rolling a 1,2,3,4,5,6 on a die
*uniform distribution*
Two parameters in uniform distribution include... - correct answer a, the
minimum possible value
b, the maximum possible value
*uniform distribution*
The probability can be determined by this formula... - correct answer
P(x1<x<x2) = (x2-x1)/(b-a)
Where x1 is greater than or equal to a;
and x2 is less than or equal to b
*uniform distribution*
The expected value for the random variable is E(x) = Avg, for a uniform
distribution the formula is... - correct answer E(x) = (a+b)/2
*normal distribution*
For normal, the two parameters are... - correct answer the mean and the
standard deviation
A ________ ___________ ________ can assume any value in an
interval on the real line or in a collection of intervals. (3 words) - correct
answer continuous random variable
*continuous distribution*
The probability of the random variable assuming a
, particular value is... - correct answer 0
*continuous distribution*
A random variable is ______________ _______________ whenever the
probability is proportional to the interval's length. - correct answer uniformly
distributed
*uniform distribution*
the variance of x equation for uniform distribution is... - correct answer Var(x)
= ((b-a)^2) / (12)
*normal distribution*
The distribution is... - correct answer symmetric
*normal distribution*
The *highest point* on the normal curve is at the
_____ which is also equal to the ________ - correct answer mean; median
*normal distribution*
the mean can be... - correct answer any numerical value
ex: negative, zero, or positive
*normal distribution*
The standard deviation determines the "__________" of the
curve: *larger values* result in ________ curves with _________ tails. -
correct answer flatness; flatter curves; thicker tails
Questions with complete solution
2025
*normal distribution*
Converting to z-scores - correct answer Subtracting the mean and dividing it
by the standard deviation
*normal distribution*
To find the probability of a value being less than or equal to x... - correct
answer 1. Convert X to a z value by subtracting mean and dividing by the
standard deviation
2. Then put in excel as =NORM.S.DIST(z,true)
*normal distribution*
To find the z-value in excel you use the excel function... - correct answer
=NORM.S.INV(probability)
This is the backwards way of finding the probability of a value being less than
or equal to x
There are two types of continuous distribution.... - correct answer Normal and
Uniform
normal distribution is.... - correct answer A function that represents the
distribution of variables as a symmetrical bell-shaped graph.
uniform distribution is... - correct answer the frequency of each value of the
variable is evenly spread out across the values of the variable
,ex: rolling a 1,2,3,4,5,6 on a die
*uniform distribution*
Two parameters in uniform distribution include... - correct answer a, the
minimum possible value
b, the maximum possible value
*uniform distribution*
The probability can be determined by this formula... - correct answer
P(x1<x<x2) = (x2-x1)/(b-a)
Where x1 is greater than or equal to a;
and x2 is less than or equal to b
*uniform distribution*
The expected value for the random variable is E(x) = Avg, for a uniform
distribution the formula is... - correct answer E(x) = (a+b)/2
*normal distribution*
For normal, the two parameters are... - correct answer the mean and the
standard deviation
A ________ ___________ ________ can assume any value in an
interval on the real line or in a collection of intervals. (3 words) - correct
answer continuous random variable
*continuous distribution*
The probability of the random variable assuming a
, particular value is... - correct answer 0
*continuous distribution*
A random variable is ______________ _______________ whenever the
probability is proportional to the interval's length. - correct answer uniformly
distributed
*uniform distribution*
the variance of x equation for uniform distribution is... - correct answer Var(x)
= ((b-a)^2) / (12)
*normal distribution*
The distribution is... - correct answer symmetric
*normal distribution*
The *highest point* on the normal curve is at the
_____ which is also equal to the ________ - correct answer mean; median
*normal distribution*
the mean can be... - correct answer any numerical value
ex: negative, zero, or positive
*normal distribution*
The standard deviation determines the "__________" of the
curve: *larger values* result in ________ curves with _________ tails. -
correct answer flatness; flatter curves; thicker tails
