Stats Flashcards
True or false
A Z-distribution belongs to the normal distribution family and serves as the standard by which other normal distributions are evaluated.
True
Describe a normal distribution
The standard deviation represents the distance from the mean to its inflection points,
The mean and median are identical
 It is symmetrical
A Z-distribution is also called
Standard scores, Z scores, Z values
What does a Z score represent?
The number of standard deviation instead of value lies above or below the mean
True or false
Standardizing does not change the probabilities of X; it only changes units
True
The process of standardizing converts what to what?
Convert an X-value to Z-value
A Z- distribution is normally distributed with a mean of _______ and standard deviation of ________
Mean of 0 and standard deviation of 1
What percent of a normal distribution lies within 1 standard deviation of the mean
68%
What percent of the normal curves values lie within 2 standard deviations of the mean
95%
What percent of a normal curves values fall within 3 standard deviations of the mean
99.7%
Almost all (99.7%) of a normal curves value falls within ______ standard deviations of the mean.
3
True or false
Standardizing does not change the probabilities for X; it only changes units
True
About _____ percent of the normal curves, values lies within two standard deviations of the mean
95%
True or false
The process of standardizing converts an X value to a Z value
True
Describe a normal distribution
It is symmetric
The mean and median are identical
The standard deviation represents the distance from the mean to its inflection points
