represents the number of data values in a population
bimodal
two modes
multimodal
more than two modes
midrange
maximum value + minimum value
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2
decimal point rule for measures of center
carry one more decimal place than is present in the original set of values
Measures of center
mean
median
mode
midrange
variance is
s2 standard diviation squared
Range rule of thumb
Minimum "usual" value = (mean) - 2 x (standard deviation)
Maximum "usual" value = (mean) + 2 x (standard deviation)
Range rule of thumb for estimating a value of the standard deviation s To roughly estimate the standard deviation from a collection of known sample data use
To roughly estimate the standard deviation from a collection of known sample data use
s = range
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4
Empirical rule
For bell shaped distributions
68-95-99.7
Chebyshev's Theorem
1-1/k2
CV
cv= s X 100%
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X
z score is rounded to
2 decimal places
z score
z= x- mean devided by s
percintile of value x
percentile of value x= number of values less than x devided by total number of values multiplied by 100
Converting from the kth percentile to the corresponding data value
Locator = K (percentile being used) devided by 100 multiplied by n (total number of values in the data set)