5.4 Mean, Median and Mode (p. 118-121)

Listen and learn this song from Harcourt called "In a Nutshell"

I.Three measures of central tendency: Mean, Median, and Mode
1. Mean: usually called "the average"
- find the mean by adding up all the values and dividing by the total number of values
2. Median: the middle number
-find the median by putting the numbers in numerical order and then finding the middle value
3. Mode: the most common number
- find the mode by identifying which number is most common in a set of data. This is easiest if the numbers have been ordered.

5.3 Frequency Tables and Line Plots (p.114-117)

I. Frequency refers to how many times something occurs or happens

• Cumulative Frequency: the running total of the frequencies - add each part together as you go down the column to show a "running total" with each item
  
• Relative Frequency: the frequency of the category divided by the sum of the frequencies (often given as a percentage of the total or shown in a graph for comparison)

I. Ways to show data: Frequency Tables and Line Plots

• A Frequency Table lists the items being recorded and tells how many times each item occurs. Sometimes tally marks are used to count the frequency. Below are two seperate examples.


• A line plot shows the frequency of data on a number line by using an "x" or other symbol

Pictures from icoachmath.com

5.2 Bias in Surveys (p.112-113)

Bias: when certain groups from a population are not represented in the sample.
Unbiased: All individuals in the population have equal chances of being selected for the survey

5.1 Samples (p.110-111)

Sampling a few people in a group is a way to find out information about a group of people. It is difficult to accurately and fairly gather information without asking everyone.

Survey: a method of gathering information about a group
Population: everyone that makes up a specific group (for example - all teenagers)
Sample: a part of the group used to represent a population
Random Sample: sample in which every person in a population has an equal chance of being selected

For example: It would be unfair to only survey your friends, and use the data as a representative of all sixth graders. Just asking your friends, means they were NOT randomly selected.

4.7 Algebra: Decimal Expressions and Equations (p.94-95)

This lesson is practice for plagging in values into algebraic expressions and equations. Please review the notes for all of chapter 4 in preparation for our chapter test on Wednesday, October 21. There are lots of practice problems in the hard cover book on page 96 and 97, in addition to the practice test which will be collected on Wednesday.