ISDS 2000 - Chapter 6
The Gaussian
- The normal probability distribution, or simply the normal distribution - Normal bell shaped curve (mean = median = mode)
The standard normal table is also referred to as what?
A Z table!
Which of the following random variables is depicted with a bell-shaped curve?
A normal random variable
The probability that the normal random variable Z is less than 1.5 is equal to?
P(Z > -1.5)
When approximating the binomial distribution using the normal distribution, what value is used for the standard deviation?
Square root of np(1-p)
What does "cumulative probability" mean?
The probability that Z is less than or equal to a given z value
The standard normal random variable zZ is a normal variable with E(Z) = ______ and SD(Z) = ________
Zero and One
The z table used in the textbook provides _______ probabilities
cumulative
Due to symmetry, the probability that the standard normal random variable Z is greater than 0 is
equal to 0.5
The normal distribution is completely described by these two parameters:
mean and variance
You use R's _______ function to find probabilities associated with the normal distribution
qnorm
If X is normally distributed random variable, then
the mean, median, and mode are all equal
We transform X into Z by subtracting from X its mean and dividing by its standard deviation, that is referred to as.....
tranformation
In order to transform a standard normal value z into its unstandardized value x, we use the following formula.....
x = μ + zσ
In order to transform a value x into it standardized value z, we use the formula....
z = (x−μ)/σ