1. © A Very Good Teacher 2008 8 th Grade TAKS Review 2008 Objective 5 Day 1

2. © A Very Good Teacher 2008 Simple Probability Probability = Example: A jar contains 4 red marbles, 2 blue marbles, and 3 yellow marbles. What is the probability that a marble drawn randomly will be red? Favorable outcomes Possible outcomes Favorable outcomes Possible outcomes red marbles Probability total marbles Obj. 5: 8.11A

3. © A Very Good Teacher 2008 Com∙pound Probability Com∙pound Probability is just several Simple Probabilities multiplied together Watch out for the words –“Replacement” –“Without Replacement” Favorable outcomes Possible outcomes Favorable outcomes Possible outcomes Com∙pound Probability = x Means you choose an object and then put it back before you choose again Means you choose an object and hold on to it while you choose again Obj. 5: 8.11A

4. © A Very Good Teacher 2008 Com∙pound Probability cont… Example: A jar contains 4 red marbles, 2 blue marbles, and 3 yellow marbles. What is the probability of drawing a red marble, replacing it, then drawing a yellow marble? Favorable outcomes Possible outcomes Favorable outcomes Possible outcomes Com∙pound Probability = x red marbles total marbles yellow marbles total marbles x 1 3 Obj. 5: 8.11A

5. © A Very Good Teacher 2008 Measures of Central Tendency There are 4 measures that fit this description: –Mean: –Median: –Mode: –Range: NumbersMiddleLikelihood Average Middle … put numbers in order 1 st Most … not all data sets have a mode *you may have to average the 2 in the middle* Biggest - Smallest Obj. 5: 8.12A

6. © A Very Good Teacher 2008 Measures of Central Tendency, cont… Example: Ruben earned the following grades on his tests in History this six weeks: 94, 72, 56, 81. Which measure of central tendency will give him the highest score? Mean (Average) = Median (Middle)56, 72, 81, 94 Mode (Most) None Range (Biggest – Smallest)94 - 56= 38 Obj. 5: 8.12A

7. © A Very Good Teacher 2008 Scatter Plots Correlation Positive Negative No Obj. 5: 8.12B

8. © A Very Good Teacher 2008 Scatter Plots, cont… Example: The scatterplot below shows the amount of time spent running each week and the body weight of the person running. Which statement best describes the relationship? Obj. 5: 8.12B A.As time decreases, weight decreases B.As time increases, weight increases C.As time increases, weight decreases D.No relationship exists

9. © A Very Good Teacher 2008 Vocabulary Probability – the likelihood than an event will occur –Replacement Measures of Central Tendency –Mean - average –Median – middle number –Mode – number that occurs most often –Range – largest minus the smallest Scatterplot – a graph of points on grid –Correlation Positive – a graph that increases from left to right Negative – a graph that decreases from left to right None – a graph that is too scattered to have correlation