ECN 221 ASU Exam 2 Review Question
and answers already passed 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
*normal distribution*
and answers already passed 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
*normal distribution*
