7 Flashcards
In a normal distribution, the curve is ____ around the parameter mu?
•Symmetric
In a normal distribution the curve never touches what?
The x axis.
Standard normal distribution?
Mean is zero and variance and standard deviation is one.
What do you use to transform a normal distribution to a standard normal distribution?
If you have a random variable with a normal distribution with a mean and variance, it can be transformed into a new random variable, Z, that will have a standard normal distribution. This is called a Z-score.
If you have a random variable X with a normal distribution with a mean and variance, it can be created from a standard normal random variable by?
Variable X with a random variable Z.
The random variable Z indicates?
The number of standard deviations that X is above or below its mean.
What is the most common random variable for standard normal distribution?
Z
What is the most common random variable for a normal distribution?
X
Why is P(Z<=5) = P(Z<5) if you have a probability density function?
Since you cannot get the probability of exactly Z=5 since you cannot get the area of an individual line.
!!!Degrees of freedom (df)?
The bigger the df’s get, the more likely the t-distribution looks like?
The standard normal distribution by the tails squishing and the height increasing.
The t-distribution is what compared to the standard normal distribution?
More variable than the standard normal distribution
