Chapter 5 Data and Probability

  • Chapter 5

    Chapter Objectives:

    * Information can be analyzed to find a typical value for a data set.

    * Data can be analyzed to predict the likelihood of an event happening.


    Average - The average or mean, is calculated by dividing the TOTAL NUMBER OR AMOUNT by THE NUMBER OF ITEMS. Ex: 3 students collected a total of 12 shells. The average number of shells collected by each student is 12 ÷ 3, or 4 shells.

    Mean - same as above

    Median - In a set of data arranged in order, the median is the middle number, or the average of the two middle numbers. Example A: 4  7  7  8  9  9  9 The middle number, the median, is the 8. Example B: 2  2  4  6  8  9  10 The median is found by adding the two middle numbers (6+8) and divide it by the amount of numbers in the median (2). 14 ÷ 2 = 7. The median is 7.

    Mode - The mode are the numbers that occur the most often in a set of data. Ex: 4  7  7  8  9  9  9 . Mode = 9

    Range - The range recognizes the difference between the greatest and the least number in a set of data. Ex: 2  4  5  5  6  8  8  9  10.   Range =  10 - 2 = 8

    Line plot - A line plot shows the frequency of data on a number line.

    Stem-and-Leaf plot - A stem-and-leaf plot is a graph that organizes data by place value.

    Outlier - An outlier is a number in a set of data that is much greater than or less than the other numbers in the data.

    Outcome - The outcome is the result in a probability experiment.

    Certain - This is a guaranteed outcome, which has a 100% chance of occurring.

    More likely - More likely is having a greater chance or probability of occurring. If the probability of the outcome is between 1/2 and a 1, it is more likely to occur.

    Equally likely - Equally likely is having the same chance or probability of occurring.

    Less likely - Less likely is having a lesser chance or probability of occurring. If the probability of an outcome is between 0 and 1/2, it is less likely to occur.

    Impossible - This means there is no chance, or having zero probability of occurring. This is an outcome that will definitely NOT occur.

    Favorable outcome - A favorable outcome is a desired result.

    Probability - Probability is the likelihood of an event occurring. Probability is the number from 0 to 1 that represents the chance of an outcome. Probability is determined by dividing the NUMBER OF FAVORABLE OUTCOMES by the NUMBER OF POSSIBLE OUTCOMES.