310 likes | 371 Views
Splash Screen. Example 7-4b. Objective. Predict the actions of a larger group by using a sample. Example 7-4b. Vocabulary. Sample. A randomly selected group chosen for the purpose of collecting data. Example 7-4b. Vocabulary. Population.
E N D
Example 7-4b Objective Predict the actions of a larger group by using a sample
Example 7-4b Vocabulary Sample A randomly selected group chosen for the purpose of collecting data
Example 7-4b Vocabulary Population The entire group of items or individuals from which the samples under consideration are taken
Example 7-4b Vocabulary Unbiased sample A sample that is selected so that it is representative of the entire population
Example 7-4b Vocabulary Simple random sample A sample where each item or person in the population is as likely to be chosen as any other
Example 7-4b Vocabulary Stratified random sample A sampling method in which the population is divided into similar, non-overlapping groups
Example 7-4b Vocabulary Systematic random sample A sampling method in which the items or people are selected according to a specific time or item interval
Example 7-4b Vocabulary Biased sample A sample drawn in such a way that one or more parts of the population are favored over others
Example 7-4b Vocabulary Convenience sample A sample which includes members of the population that are easily accessed
Example 7-4b Vocabulary Voluntary response sample A sample which involves only those who want to participate in the sampling
Lesson 7 Contents Example 1Describe Samples Example 2Describe Samples Example 3Using Sampling to Predict Example 4Using Sampling to Predict
Example 7-1a To determine which school lunches students like most, every twentieth student to walk into the cafeteria is surveyed. Describe the sample. Random sample Every 20th student is surveyed Unbiased Population is those entering cafeteria Answer: Random, unbiased 1/4
Example 7-1b To determine which CDs customers like most, every tenth customer to walk into the music store is surveyed. Describe the sample. Answer: Unbiased, random 1/4
Example 7-2a To determine what sports teenagers like, the student athletes on the girls’ field hockey team are surveyed. Describe the sample. Girl’s on field hockey team are more likely to choose hockey as favorite sport Biased Convenience Only the hockey team is survey Answer: Biased, Convenience 2/4
Example 7-2b To determine what restaurant teenagers like, the teenagers eating at Pete’s Diner are surveyed. Describe the sample. Answer: Biased, Convenience 2/4
Book Type Number of Students mystery 12 adventure novel 9 sports 11 short stories 8 Example 7-3a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. What percent of the students prefer mysteries? Write proportion to find percent 3/4
Example 7-3a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. What percent of the students prefer mysteries? x z Remember: Percent has a denominator of 100 100 Define the variable The second ratio is based on preference of mystery books to total books 3/4
Example 7-3a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. What percent of the students prefer mysteries? x z = The denominator is the total surveyed 100 40 The numerator is how many prefer mysteries 3/4
Book Type Number of Students mystery 12 adventure novel 9 sports 11 short stories 8 Example 7-3a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. What percent of the students prefer mysteries? x z 12 = 100 40 12 preferred mysteries 3/4
Example 7-3a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. What percent of the students prefer mysteries? Cross multiply x z 12 = 100 40 Multiply 40x = 12(100) Ask “What is being done by the variable?” 40x = 1200 The variable is being multiplied by 40 Do the inverse on both sides of the equal sign 3/4
Example 7-3a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. What percent of the students prefer mysteries? Using a fraction bar, divide both sides by 40 x z 12 = 100 40 Combine “like” terms 40x = 12(100) Use the Identity Property to multiply 1 x 40x = 1200 40 40 1 x = 30 Add dimensional analysis Answer: x = 30 % 3/4
Type Number gel pens 22 ball point 8 glitter pens 10 roller balls 10 Example 7-3b PENSThe student shop sells pens. It surveys 50 students at random. The pens they prefer are in the table. What percent of the students prefer gel pens? Answer: x = 44% 3/4
Book Type Number of Students mystery 12 adventure novel 9 sports 11 short stories 8 Example 7-4a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. If 220 books are to be sold at the book fair, how many should be mysteries? Write proportion 4/4
Book Type Number of Students mystery 12 adventure novel 9 sports 11 short stories 8 Example 7-4a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. If 220 books are to be sold at the book fair, how many should be mysteries? 12 First ratio is taken from the chart about the survey 4/4
Book Type Number of Students mystery 12 adventure novel 9 sports 11 short stories 8 Example 7-4a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. If 220 books are to be sold at the book fair, how many should be mysteries? 12 40 Total surveyed is denominator 4/4
Example 7-4a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. If 220 books are to be sold at the book fair, how many should be mysteries? The next ratio will be based on how many actually were sold 12 x = 40 220 The total books sold will be the denominator Define the variable 4/4
Example 7-4a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. If 220 books are to be sold at the book fair, how many should be mysteries? Cross multiply 12 x Multiply = 40 220 Ask “What is being done by the variable?” 40x = 12(220) 40x = 2,640 The variable is being multiplied by 40 Do the inverse on both sides of the equal sign 4/4
Example 7-4a BOOKSThe student council is trying to decide what types of books to sell at its annual book fair to help raise money for the eighth-grade trip. It surveys 40 students at random. The books they prefer are in the table. If 220 books are to be sold at the book fair, how many should be mysteries? Using a fraction bar, divide both sides by 40 12 x = 40 220 Combine “like” terms 40x = 12(220) Use the Identity Property to multiply 1 x 40x = 2,640 40 40 Add dimensional analysis 1 x = 66 Answer: x = 66 mystery books 4/4
Type Number gel pens 22 ball point 8 glitter pens 10 roller balls 10 Example 7-4b * PENSThe student shop sells pens. It surveys 50 students at random. The pens they prefer are in the table. If 300 pens are to be sold at the student shop, how many should be gel pens? Answer: x = 132 gel pens 4/4
End of Lesson 7 Assignment