Chapter 3: The normal distributions Flashcards
What is a density curve?
It describes the overall pattern of a distribution
On a density curve where do we find the probability of an event?
Area under the curve
On a density curve, the total area under the curve must equal ____
1
a uniformed distribution in a density curve is _____
symmetric
unimodal
constant across the x interval of which they are defined
How do you find the proportion on a density curve?
area=(base)(1/5)
The median (μ) of a density curve is
the point that divides the area under the curve in half
the point that divides the area under the curve in half is called the
equal areas point
In a symmetric density curve the mean and median are ______
the same
In a skewed density curve the mean and median is ______
not the same. The mean is closer to the tail
In a density curve, the mean is shown as ____ and the standard deviation is shown as _____
μ
σ
what is a normal distribution?
a probability distribution that is symmetric about the mean
What is the shape of a normal distribution?
Symmetric, unimodal, bell shaped
What causes a normal distribution to shift horizontally?
Changing the mean
What causes a normal distribution spread to change
changing the standard deviation
What is the 68-95-99.7/ the empirical rule?
approximately 68% of the observation fail with 1 standard deviation of the mean
approximately 95% of the observations fail within 2 standard deviations of the mean
approximately 99.7% of the observations fail within 3 standard deviations of the mean
