Data Analysis Flashcards
relative frequency
occurence
total
(percentage/decimal/fraction)
Scatterplots: how to find the rate of change
take points from each end of the trend line (not actual data
change in Y variable
change in X variable
(Y vars per Xs)
Percentiles of the quartiles
L
Q1: 25
M/Q2: 50
Q3: 75
G
Range
affected by outliers?
Max - min
yes
Interquartile range
Q3 - Q1
standard deviation
average of the spread from the mean
how to calculate SD
- Find mean
- Find difference between mean and each value
- Square those
- Find the average of those squares
- SD is the non-negative square root of that number
finding how many SDs above/below the mean a number is
number - mean = difference
difference/SD = # of SD above mean
How to standardize
what does it show
subtract the mean from each value and then divide by the SD
-measures the data position relative to the other points of data
S (upside down u) T
intersection
all elements that are in both S and T
S U T
union
all in S or T or both
inclusion-exclusion principle
|A U B| = |A| + |B| - |A Π B|
multiplication principle
1st choice has k possibilities
2nd has m possibilities and is independent from #1
km = the number of possible combinations of the two choices
permutations
order matters
n!
(n-k)!
combinations
order doesn’t matter
n!
k! (n-k)!
