March 10, Monday, March 10th. 1. Bell Work: Week #5 OAA. 2. Vocabulary: Sampling Ch. 9-1 MB pg Notes/Examples: Sampling Ch.

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1 Monday, March 10th 1. Bell Work: Week #5 OAA 2. Vocabulary: Sampling Ch. 9-1 MB pg Notes/Examples: Sampling Ch. 9-1

2 1. Bell Work: Students' Lesson HeightsObjective: Students 2. Vocabulary: will identify Ch. 9.1 sampling methods and recognize 3. Notes/Examples: biased Ch. 9.1 samples 4. HW: MB pg. 464 #8-20 HW: MB pg. 464 #8-20

3 Learn to identify sampling methods and to recognize biased samples. Math Book page 462 Vocabulary population sample random sample systematic sample stratified sample convenience sample voluntary-response sample biased sample OH Academic Content Standards 8.5.7; 8.5.9

4 V.I.P. Vocabulary The population is the entire group being studied. The sample is the part of the population being surveyed.

5 ONE MORE TIME!!!! This must really be important! Population - the entire group being considered for a survey Sample - the part of the population being surveyed

6 To get accurate information, it is important to use a good sampling method. In a random sample, each member of the population has an equal chance of being selected. A random sample is best, but other methods can be used.

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8 Systematic Sampling A sample of the population that has been selected using a pattern.

9 Stratified Sampling A sample of a population taken at random from randomly chosen subgroups

10 Convenience Sampling A sample based on members of the population that are easiest to reach

11 Voluntary-response a.k.a Self-selected A sample in which members choose to be in the sample

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13 The larger the sample size, the better your sample will represent the entire population.

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15 A. Random B. Systematic C. Stratified D. Convenience E. Voluntary-Response March 10, 2014

16 A. Random B. Systematic C. Stratified D. Convenience E. Voluntary-Response March 10, 2014

17 A. Random B. Systematic C. Stratified D. Convenience E. Voluntary-Response March 10, 2014

18 A. Random B. Systematic C. Stratified D. Convenience E. Voluntary-Response March 10, 2014

19 A. Random B. Systematic C. Stratified D. Convenience E. Voluntary-Response March 10, 2014

20 A. Random B. Systematic C. Stratified D. Convenience E. Voluntary-Response March 10, 2014

21 A. Random B. Systematic C. Stratified D. Convenience E. Voluntary-Response March 10, 2014

22 A. Random B. Systematic C. Stratified D. Convenience E. Voluntary-Response March 10, 2014

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24 Math Humor Did you hear the news that everyone in the world now has a telephone? In a recent survey, 100% of the people who were called said that they had one. March 10, 2014

25 A fitness magazine printed a readers survey. Statements 1, 2, and 3 are interpretations. Which do you think the magazine would use? 1. The average American exercises 3 times a week. 2. The average reader of this magazine exercises 3 times a week. 3. The average reader who responded to the survey exercises 3 times a week.

26 People who read fitness magazines are likely to be interested in exercise. This could make the sample biased in favor of people who exercise more times per week. March 10, 2014

27 Sometimes, these sampling methods result in biased samples. A biased sample does not accurately represent the population. The data collected from biased samples is not reliable.

28 Identifying Biased Samples A radio station manager chooses 1500 names from the local phone book to survey people about their listening habits. Population Sample Possible Bias People in the local area Up to 1500 people who take the survey Not all people are in the phone book

29 An advice columnist asks her readers to write in with their opinions about how to hang the toilet paper on the roller. Population Sample Possible Bias Readers of the column Readers who write in Only readers with strong opinions write in.

30 An eighth grade student council member polls classmates about a new school mascot. Population Sample Possible Bias

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37 The United States Census Bureau conducts a survey every ten years to determine the population of the United States. The first U.S. census taken was in Two hundred men rode on horseback to count the number of people in each household, and data was recorded on small scraps of paper. This census cost the government just $45,000! Until 1960, the population survey was conducted mostly door to door. At that time, bureau officials realized that this method was inefficient because the population was growing rapidly and becoming more mobile and diverse. By 1980, 90% of the census was taken by mail. March 10, 2014

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40 Town A: # of households with plants total number of households = Town B: # of households with plants total number of households = The percent of households with houseplants in Town A (42%) is close to the national percent. The percent of households in Town B (56%) is greater than the national percent.

41 Town A: # of households with pet fish total number of households = Town B: # of households with pet fish total number of households = The percent of households with pet fish in Town A (25%) is close to the national percent. The percent of households in Town B (55%) is greater than the national percent.

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44 HW: MB page 464 #8-20 March 10, 2014

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46 Population: sample: possible bias: deli customers; Sunday s customers; the sample does not include weekday customers. Population: sample: people who attend the team s games; people other than season ticket holders attend baseball games.

47 Every fifth name is called. The sample is conveniently in the hair salon. The teacher draws a question at random from the box. The visitors to the web site have chosen to be in the sample. Each study group is a randomly chosen subgroup; one person is selected at random from each one.

48 Population: sample: possible bias: students; students who buy the entrée; the student who buy the entrée may be the people who like the food in the cafeteria. Population: sample: possible bias: city residents; people attending the city council meeting; most citizens do not attend city council meetings. Population: sample: possible bias: trees; trees along the river; the trees sampled have a better source of water than the others.

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