Probability, Mode/Median/Range, Graphing Studyguide



Math SCA Study Guide

Mode/Median/Range

The median is the number that is the number in the middle when a group of numbers is arranged in order from least to greatest.

The mode is the number that occurs most often in a set of data.

To find the range of a set of data, you subtract the least number from the greatest number.

Example: 20, 25, 26, 26, 26, 26, 32, 33, 34, 34, 35, 37, 39

Median is 32

Mode is 26

Range is 19

Probability

Probability is the chance that a given event will or will not happen.

To find the probability of events, follow the following steps below.

• Find out the number of successful outcomes.

• Find out the total number of possible outcomes.

• Write the probability as a fraction.

Probability (P) = successful outcomes

possible outcomes

Example: What are the possible outcomes when tossing a coin once?

Possible outcomes: 2 heads or tails

Probability of getting heads successful outcomes 1

possible outcomes 2

Example: What are the possible outcomes of rolling an even number on rolling a dice?

Possible outcomes: 1, 2, 3, 4, 5, 6

Probability of rolling an even number successful outcomes 3

possible outcomes 6

Example Problem: There are four different types of cookies in a bag. There are 4 chocolate chip, 5 sugar cookies, 2 peanut butter, and 1 walnut in the bag. Sam randomly pulls one cookie out of the bag to eat without looking. What is the probability that the cookie Sam pulls out is chocolate chip?

Possible outcomes: 4 chocolate chip, 5 sugar, 2 peanut, 1 walnut total of 12 cookies

Probability of picking a chocolate chip cookie = successful outcomes 4

possible outcomes 12

Graphing

Types of graphs that we have covered:

• Line graphs

• Bar graphs

• Pie chart or circle graphs

• Tally and Frequency Charts

• Pictographs

Pictographs: Use symbols or pictures to represent numbers on a graph. Look for the key when reading information in a Pictograph.

Bar graphs: Use bars of different length to show data. Look for title, labels on the horizontal and vertical axes, and scale intervals when reading information in a Bar Graph.

Line graphs: Use points and lines to show changes over a period of time in a set of data. Look for title, labels on the horizontal and vertical axes, and scale intervals when reading information in a Line Graph.

Circle graphs: Represent data by dividing a circle into parts of a whole using percentages or numbers. Look for tile, labels, percentages and numbers when reading information in a circle graph.

When interpreting graphs, make sure to look for the following items in the graphs.

• Type of Graph

• Graph’s title

• Graph’s horizontal and vertical axis labels

• Graph Labels

• Graph’s scale and intervals

• Graph’s key

• Trends or patterns in the graph

READ EACH TYPE OF GRAPH CAREFULLY

Collecting Data and Graphing

Steps to follow when collecting data:

• Choose a place, time, and method to collect data each time

• Record the data to be graphed

• Choose the best type of graph to display the data

• Graph the data

• Interpret, analyze, and draw conclusions about the data

Reading Venn Diagrams

Venn diagrams are a way to sort and represent data. They show groups that are alike and groups that are different. The part of the groups that overlap is the part that is alike.

For example:

Owners of pets

Dog Owners Cat Owners

Jamie gathered information bout some of the pets owned by her friends. She recorded the data in a Venn diagram.

How many friends own only dogs? 8

How many friends own only cats? 5

How many friends own cats and dogs? 6

How many friends own a dog? 8 + 6 = 14

How many friends own a cat? 5 + 6= 11

IT IS ALWAYS IMPORTANT TO LOOK AT EACH SECTION OF THE DIAGRAM CAREFULLY AS WELL AS READING EACH QUESTION ABOUT THE DIAGRAM CAREFULLY.

Predicting the Likelihood of and Event

Using words, you can describe the likelihood that an event will occur as certain, likely, unlikely, or impossible.

An event is impossible if it will never happen. This is represented by O.

An event is certain if it will always happen. This is represented by 1.

An outcome is likely to occur if it will happen more than half of the time.

An outcome is unlikely to occur if it will happen less than half of the time.

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