Pre-Algebra Chapter 6 - Ramsey School District

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A Preview of Lesson 6-9 Taking a Survey The graph shows the results of a survey about what types of stores people in the United States shop at the most. Since it would be impossible to survey everyone in the country, a sample was used. A sample is a subgroup or subset of the population. It is important to obtain a sample that is unbiased. An unbiased sample is a sample that is: • representative of the larger population, • selected at random or without preference, and • large enough to provide accurate data. Source: International Mass Retail Association To insure an unbiased sample, the following sampling methods may be used. • Random The sample is selected at random. • Systematic The sample is selected by using every nth member of the population. • Stratified The sample is selected by dividing the population into groups. Model and Analyze Tell whether or not each of the following is a random sample. Then provide an explanation describing the strengths and weaknesses of each sample. Type of Survey Location of Survey 1. travel preference mall 2. time spent reading library 3. favorite football player Miami Dolphins football game 4. Brad conducted a survey to find out which food people in his community prefer. He surveyed every second person that walked into a certain fast-food restaurant. Identify this type of sampling. Explain how the survey may be biased. 5. Suppose a study shows that teenagers who eat breakfast each day earn higher grades than teenagers who skip breakfast. Tell how you can use the stratified sampling technique to test this claim in your school. 6. Suppose you want to determine where students in your school shop the most. a. Formulate a hypothesis about where students shop the most. b. Design and conduct a survey using one of the sampling techniques described above. c. Organize and display the results of your survey in a chart or graph. d. Evaluate your hypothesis by drawing a conclusion based on the survey. 62.4% Discount stores 15.6% National chains 22.0% Conventional stores Investigating Slope-Intercept Form 309 Algebra Activity Taking a Survey 309
Probability and Predictions Vocabulary • outcomes • simple event • probability • sample space • theoretical probability • experimental probability • Find the probability of simple events. • Use a sample to predict the actions of a larger group. can probability help you make predictions? A popular word game is played using 100 letter tiles. The object of the game is to use the tiles to spell words scoring as many points as possible. The table shows the distribution of the tiles. a. Write the ratio that compares the number of tiles labeled E to the total number of tiles. b. What percent of the tiles are labeled E? c. What fraction of tiles is this? d. Suppose a player chooses a tile. Is there a better chance of choosing a D or an N? Explain. Letter Number of Tiles E 12 A, I 9 O 8 N, R, T 6 D, L, S, U 4 G 3 B, C, F, H, M, P, V, W, Y, blank 2 J, K, Q, X, Z 1 PROBABILITY OF SIMPLE EVENTS In the activity above, there are 27 possible tiles. These results are called outcomes. A simple event is one outcome or a collection of outcomes. For example, choosing a tile labeled E is a simple event. You can measure the chances of an event happening with probability. Study Tip Probability Each of the outcomes must be equally likely to happen. • Words • Symbols Probability The probability of an event is a ratio that compares the number of favorable outcomes to the number of possible outcomes. number of favorable outcomes P(event) number of possible outcomes The probability of an event is always between 0 and 1, inclusive. The closer a probability is to 1, the more likely it is to occur. impossible to occur equally likely to occur 1 1 3 0 or 0.25 or 0.50 or 0.75 1 4 2 4 0% 25% 50% 75% 100% certain to occur Concept Check Suppose there is a 45% chance that an event occurs. How likely is it that the event will occur? 310 Chapter 6 Ratio, Proportion, and Percent
Page 1 and 2: Ratio, Proportion, and Percent •
Page 3 and 4: Ratios and Rates Vocabulary • rat
Page 5 and 6: Study Tip Look Back To review dimen
Page 7 and 8: Standardized Test Practice Extendin
Page 9 and 10: Using Proportions Vocabulary • pr
Page 11 and 12: TEACHING TIP Solve juice in origina
Page 13 and 14: 41. SNACKS The Skyway Snack Company
Page 15 and 16: Scale Drawings and Models Vocabular
Page 17 and 18: Interior Designer Interior designer
Page 19 and 20: 21. CRITICAL THINKING What does it
Page 21 and 22: To write a fraction as a percent, w
Page 23 and 24: Practice and Apply Homework Help Fo
Page 25 and 26: A Preview of Lesson 6-5 Using a Per
Page 27 and 28: Using the Percent Proportion • Us
Page 29 and 30: Example 4 Find the Part What number
Page 31 and 32: 25. LIFE SCIENCE Carbon constitutes
Page 33 and 34: Find the percent of each number men
Page 35 and 36: Practice and Apply Homework Help Fo
Page 37 and 38: Using Percent Equations Vocabulary
Page 39 and 40: Simple interest is the amount of mo
Page 41 and 42: 42. CRITICAL THINKING Determine whe
Page 43 and 44: Percent of Change Vocabulary • pe
Page 45 and 46: PERCENT OF DECREASE When the amount
Page 47: Standardized Test Practice 26. RESE
Page 51 and 52: USE A SAMPLE TO MAKE PREDICTIONS No
Page 53 and 54: Standardized Test Practice 37. FOOD
Page 55 and 56: Vocabulary and Concept Check base (
Page 57 and 58: Chapter 6 Study Guide and Review 6-
Page 59 and 60: • Extra Practice, see pages 736-7
Page 61 and 62: Part 1 Record your answers on the a

Pre-Algebra Chapter 6 - Ramsey School District

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