Statistics & Probability Ms. Crusenberry 10-2013 Statistics & Probability

Vocabulary Statistics – the collection, organization and interpretation of numerical data Probability – the likelihood of a certain event occurring expressed in a ratio or a fraction

Mean, Median, Mode & Range Mean – the average of a set of numerical data Median – the number in the middle of a set of numerical data Mode – the number that appears most often in a set of numerical data Range – the difference between the highest and lowest number is a set of numerical data

Mean Add the numbers in the numerical set and then divide the sum by the number of amounts you added Ex. 10, 20, 15, 30 10+ 20+ 15 + 30 = 75 ÷ 4 = 18.75

Median Put the numbers in numerical order, find the middle numbers, add them and then divided by two, if you have an even set of numbers. If an odd set of numbers, the median is just the middle number. Ex. 5, 10, 15, 20, 25, 30 middle numbers are 15 and 20 15 + 20 = 35 ÷ 2 = 17.5 Ex. 3, 6, 9, 12, 15 the middle number is 9

Mode Put all of the numbers in numerical order Ex: 1, 5, 5, 6, 8, 11 the number that repeats the most often is the 5

Range Subtract the lowest number from the highest number in the numerical set Ex: 5, 10, 2, 25, 18 25 – 2 = 23

Practice Find the mean, median, mode and range of numerical set below. 56 61 49 32 90 75 23 101 32 mean = __________ median = _________ mode = ___________ range = ___________

Answers Mean = 57.67 Median = 56 Mode = 32 Range = 78

Probability P = number of favorable outcomes total number of outcomes possible There are five ways to show probability: fraction, decimal, ratio, percent, and words. ½ .5 1:2 50% The chances are one in two. There is a fifty percent or fifty-fifty chance.

Let’s practice A number cube with its sides numbered 1 through 6 is rolled twice. What is the probability of rolling a 2 and then a 5? **taken from Brown TABE D book a. 1/36 b. 11/30 c. 1/25

Answer A is the correct answer. The probability of a 2 being rolled is 1/6, and the probability of a 5 being rolled is 1/6. **taken from Brown TABE D book 1/6 x 1/6 = 1/36

Let’s Practice Investigating Probability, Level D Blue Book page 152