#Solving quadratic equations cheat sheet plus

Round up to the next integer for any decimal. To find R 100, the percentile rank of a data value, use this formula: Percentiles: section the distribution into 100 approximately equal hudredths (1%) Note: quintiles are ranked ass backwards - from best to worst. Quintiles: section the distribution into 5 approximately equal fifths (20%) Remember - it tells us nothing about the mean or average of the data.

If data count is even, Q 2 is the average of 2 data. If data count is odd, Q 2 is a data value. Make a box-and-whisker plot using minimum, Q 1, Q 2, Q 3, and the maxium. Quartiles: section the distribution into 4 approximately equal quarters (25%) Measurement Errors during data analysis and lack of data because of a low response rate cause bias as well. Sources of bias: inappropriate sampling methods such as poor wording of the question, lack of relevance, the range of the sample (too local), the sample size. In questions where we have to find how many of a specific group to include in the sample, we use proportion. Representative sampling: the data must be gathered from samples that represent all parts of the target population.

ex: testing the strength of bridges.ĭata can be collected by phone interviews, direct observation, printed questionnaires, internet surveys, mechanical devices (counters in turnstiles), or from archived data - such as weather data, medical records about birth and death, etc. Study: data is collected and analyzed by experts. A poll usually involves opinion (politics) Survey or poll: collects data on a sample. Symmetric form:, a = x-intercept and b = y-intercept.Ĭensus: collects data on every member of the population. Watch for fractions instead of ratios.įor general form: cross multiply, put everything on one side = 0įor standard form: multiply by x x 1 and transpose y 1. Point of division: make similar triangles of part to whole. *** Sometimes points are given in function form: f( 2) = 5 is the same as ( 2, 5) ***ĭistance between points: (it's Pythagoras!)ĭistance from pt to line: P( x 1, y 1) line: A x + B y + C = 0ĭistance between parallel lines: find a point (intercept) on 1 line and use formula above.

#Solving quadratic equations cheat sheet plus

Make it (x + 7) 2 = 19 take plus or minus sq. ** watch for these easy ones from the standard form: (x + 7) 2 19 = 0 Quadratic equations: relate to zero, then either:ġ) factor, set each factor = 0, and solveĢ) use quadratic formula to find solution. Multiplication and division: cancel terms in top and bottom that = 1.Īddition and subtraction: find common denominator - create single fraction Grouping: ab + ac db dc = a (b + c) d (b + c) = (b + c) (a d)Ģ) difference of squares: 4x 2 25y 2 = (2x + 5y)(2x 5y)ģ) trinomials: Check your middle term!! if simple - use analysis. Negative exponents: turn things into fractions.įactoring:đ) common factor: ab + ac = a (b + c) Root squared: remember that anything squared is POSITIVE!ġ) monomial denominator : (don't forget to reduce!)īased on difference of squares : (a + b)(a b) = a 2 b 2

Binomial squared: (a + b) 2 = a 2 + 2ab + b 2 (get a TRINOMIAL!)