Studied by 10 peopleIndividuals
objects described by a set of data; can be people, or animals or things
Variable
characteristics of an individual
Categorical variable
places an individuals into one of several groups or categories
Quantitative variable
takes numerical variables
Distribution
tells what values take the variable and how often it takes places
SOCS
Describes the overall pattern of a distribution
Spread - lowest and highest value
Outlier - unusual values
Center - approximate average
Shape - symmetry or skewed
Symmetric
Mean = Median
Skewed Left
Mean < Median
Skewed Right
Mean > Median
Mean
the average; add all the values and divide by the number of observations
Median
the midpoint
Five-number summary
Minimum, Q1, M, Q3, Maximum
Interquartile range (IQR)
Q3-Q1=IQR
Outlier Rule (using IQR)
Low outliers - Q1-1.5(IQR), High outliers - Q3 + 1.5(IQR)
Standard deviation
the average of the squares of deviations of the observations from their mean
Density Curve
describes the overall pattern of a distribution; always on or above the horizontal axis and has an area of 1 beneath it
Median of a density curve
the equal-areas point, the area under the curve in half
Mean of a density curve
the balance point
Normal distribution
a curve that is symmetric and based on a continuous variable
68-95-99.7 Rule
68% of the observations fall within 1σ of the mean μ, 95% of the observations fall within 2σ of the mean μ, and 99.7% of the observations fall within 3σ of the mean μ.
Z-score
the standardized value; used the formula z=x-μ/σ
Calculator functions
Inverse normal
x = μ+z(σ)
Note
Flashcard