Definitions

Definitions Mode - the value that occurs most frequently Find the Mode 5, 3, 7, 2, 4, 4, 2, 4, 8, 3, 4, 3, 4

Definitions Median - The central value of an ordered distribution Order the data from smallest to largest For a distribution with an odd number of data values, Median = Middle data value For a distribution with an even number of data values, Median= (Sum of middle values)/2

Definitions Find the Median 18, 19, 19, 27, 28 Answer: 19 18, 19, 19, 27, 28, 35 Answer: (19+27)/2 = 23 Cards

For an ordered data set of size n, Definitions For an ordered data set of size n, Position of the middle value = (n+1)/2 Cards

12 13 14 15 16 17 18 19 20

Mean =(Sum of all entries)/Number of entries Definitions Mean =(Sum of all entries)/Number of entries Find the mean: 58, 67, 60, 84, 93, 98, 100 Answer = (58 + 67 + 60 + 84 + 93 + 98 + 100)/7 = 80 Cards

Definitions Summation Symbol Σ Σx= Sum of all given x values X - the mean of a sample distribution (Read “x bar”) X=Σx/n Where n = number of data values in the sample

Definitions - (pronounced “mew”) Used to represent the mean when the data comprise the entire population = Σx/N Where N = number of data values in the population Cards

Definitions Resistant measure - one that is not influenced by extremely high or low data values Generally referred as a scale (more resistant, less resistant) Mode is a resistant measure Mean is not a resistant measure Cards

Definitions Trimmed Mean - The mean of the data values left after “trimming” a specified percentage of the smallest and largest data values from the data set. More resistant Usually 5% is used Cards

Definitions Trimmed Mean - How to Calculate Order data from smallest to largest Delete established percentage of data from the top and bottom. (Round percentages) Compute the mean of the remaining percentage Cards

Definitions Trimmed Mean - 14 20 23 25 30 35 40 42 50 80 Cards

Definitions Weighted average - Weighted Average = Σxw/Σw Where x is a data value and w is the weight assigned to that data value. The sum is taken over all data values. Cards

Example Assume Tests are worth 50% of your grade, Quizzes 20 %, and daily work 30%. If you received an average of 95% in tests, 88% in quizzes, and 100% in daily work, what is your final grade?

Pg. 89 1, 2, 4, 12, 13, 18, 20