Relative: frequencies divided by total data values

Percentage: relative x 100

Frequency polygon: line graph; pie chart

Mean: sum of all values / total # of values OR for each (add) freq(value) / total freq of values

Median: the middle number of the set, or split diff

Mode: occurs most frequent, only bi-modal or no mode

Range: subtract the lowest from highest in data set

Standard Deviation: the sq. root of [{for each} (data value â€“ mean)^{2} / number of data values

Draw the bell curve. Make sure to account for the other half in the answer (50% above or below)

Std Dev. Grouped: the sq. root of [{for each} freq (midpoint â€“ mean)^{2} / total frequencies]

Normal Distribution: z = (data value â€“ mean) / standard deviation

Margin of Error: Margin = z value / 2 (sq. root of population) [confidence/2 then look up area.]

Regression Line: Table of values: x | y | x^{2} | xy, and sum of each column. where âˆ‘ = sum n = # of points
y = a + bx b = [nâˆ‘(xy) â€“ (âˆ‘x)( âˆ‘y)] / [nâˆ‘ (x^{2}) â€“ (âˆ‘x)^{2}] a = [âˆ‘y â€“ b(âˆ‘x)] / n

Percent: out of 100

Percent to Decimal: Move decimal 2 & drop %

Fraction <-> Decimal key

Retail: Price + Markup

% Inc or Dec: amount of inc or decrease / base starting amt (use the inverse of the percent if needed)

Simple Interest rate: I = Prt (principal x rate x time)

Amount Simple Int. Acct: A = P(1 + rt)

Compound/Nominal rate: A = P(1+r)^{n} [r = periodic interest rate = (annual rate / periods per yr) and n= number of time periods = (years x periods per yr)]

Compound interest over time. Calculate each period. Then add all. Make sure n & r are correct! Make sure time is all in the same units (years vs. months)! Don’t remove negative w/1.

Effective Interest Rate: r_{eff} = (1 + r)^{n} â€“ 1 [r = periodic interest rate and n = number of periods per year)

To get rid of exponent: move n outside number, LN both side 5^{12n} = 25 â€¦ 12n(ln5) = (ln25)

Annuity (fixed deposit)r = periodic rate n = # of deposits