UNIT 3: Statistics, Data Analysis, and Probability

Period: 2, 4, 6: 1/8/13 Period 3, 5: 1/9/13 6PS 1.1 Mean, Median, Mode

MODE: Mode is the most frequently occurring number in a set. Example: For the set [3, 2, 8, 2, 4] The number that appears most often is 2, so 2 is the mode.

Big Note: Some sets will have multiple modes. Example: For the set [3, 2, 8, 2, 4, 3] The numbers that appear most often are both 2 and 3, so the modes of this set are 2 and 3.

continued…Mode For the set [3, 2, 8, 4] Since no numbers appear more than any other numbers, there is no mode for this set.

White Board CFU The data below shows the number of kilowatt-hours of electricity used last month at each of the houses on Harris street. 620, 570, 570, 590, 560, 640, 590, 590, 580 What is the mode of this data?

Mean Mean is often referred to as the “average” of a set of numbers. To find the mean, add up all the values, and divide the sum by the number of values in the set. MEAN= (sum of a group of numbers) (NUMBER of numbers in the group)

Example In calculating mean… If the values are 15, 45, and 33 The sum is =93 The number of numbers in the set is 3 So 93÷3=31

Whiteboard CFU Parisa’s four math test scores were 7, 8, 10, and 6. Hector’s test scores were 6, 7, 9, and 10. Charles’ test scores were 8, 10, 10, and 9. What is Hector’s mean score?

Whiteboard CFU Parisa’s four math test scores were 7, 8, 10, and 6. Hector’s test scores were 6, 7, 9, and 10. Charles’ test scores were 8, 10, 10, and 9. Who had the highest mean?

Median Median is the middle number in an ordered set. You must put the numbers in order. In an even set of numbers, the median is the mean of the two middle terms.

Example #1 For the set [3, 7, 8, 2, 4] These numbers aren’t in order, so place them in order:

continued… 2, 3, 4, 7, 8 The middle number is 4, so 4 is the median.

Whiteboard CFU Find the median for the following set [3, 7, 8, 2, 4, 6]

ANSWER 4 and 6 are both in the middle The average of 4 and 6= 5, so the median of this set is 5.

Independent Practice 6PS 1.1 Find mean, median, and mode 1) 18, 18, 15, 18, 18, 2) 94, 69, 84, 69, 90 3) 4, 18, 18, 23, 23, 19, 8, 4) 12, 15, 16, 17, 15, 17 5) 16, 3, 3, 3, 8, 24 6) 22, 5, 22, 13, 12, 24, 7) 23, 1, 1, 18, 1, 3, 18, 3 8) 23, 10, 2, 6, 10, 14, 1