Bellwork Find the mean, mode, range for the following data

1, 5, 3, 2, 4, 4, 2, 3, 4, 5

Mean = 33

10= 3.3

Mode = 4

Range = 4

1, 2, 2, 3, 3, 4, 4, 4, 5, 5

Median = 7

2= 3.5

1 2 3 4 5 6 7 8 9 10

Least (min) = 1

Greatest (max) = 5

Lower Q=

Upper Q=

2

4

Box and Whisker Review

BOX AND WHISKER REVIEW

Use the box-and-whisker plots below to answer each question.

Which shoe store has a greater median?

The median number of shoes sold in one week at Green’s Shoe Store, about 32, is greater than the median number of shoes sold in one week at Maroon’s Shoe Store, about 28.

20 24 26 28 30 32 34 36 38 40 42 44 t Number of Shoes Sold in One Week at Each Store

Maroon’s Shoe Store

Green’s Shoe Store

BOX AND WHISKER Review

Use the box-and-whisker plots below to answer each question.

Which shoe store has a greater interquartile range?

Maroon’s shoe store has a longer box, so it has a greater interquartile range.

20 24 26 28 30 32 34 36 38 40 42 44 t Number of Shoes Sold in One Week at Each Store

Maroon’s Shoe Store

Green’s Shoe Store

BOX AND WHISKER Review

Use the box-and-whisker plots below to answer each question.

Which shoe store appears to be more predictable in the number of shoes sold per week?

The range and interquartile range are smaller for Green’s Shoe Store, so the number of shoes sold per week is more predictable at. Green’s Shoe Store.

20 24 26 28 30 32 34 36 38 40 42 44 t Number of Shoes Sold in One Week at Each Store

Maroon’s Shoe Store

Green’s Shoe Store

Answer the following questions

City A = 460

City B = 450

City B = 475-440=35City A=550-425=125

City A=600-350=250City B = 625-350=275

Unit 1Chapter 7Section 8

Populations and SamplesPg. 412

EQ:How do you compare and analyze sampling methods?

Definitions Population: the entire group of objects or

individuals considered for the survey Sample: part of the population

Random Sample: a sample in which each member of the population has an equal chance of being selected

Definitions continued…

Convenience Sample: sampling the most available subjects in the population to obtain a quick result

biased sample: a sample that does not fairly represent the population

Populations and Samples Video Clip http://player.discoveryeducation.com/index.cfm?guidAssetId=D24D0978-BB7A-428E-94D7-855550A56B56&blnFromSearch=1&productcode=US

Write down 3 facts about samples and populations from the video.

Use complete sentences. 1. 2. 3.

Example 1Example 1Determine which sampling method will better represent the entire population. Justify your answer.

Sampling methodMaria surveys only the band students she knows personally.

Results84% want blue uniforms

Jon writes each band student’s name on a card. He questions those students whose name he draws.

61% want blue uniforms

Jon’s sample is a random sample, giving every band member equal chance to be surveyed, so it is the better method.

Convenience sample

Random sample

Turn to page 414 and answer

questions 1 and 5

Practice

Daria’s survey is better because she has randomly selected customers from the store.

Practice

Vonetta’s method is best because she uses a random sample.

Example 2Example 2Determine whether each sample may be biased. Explain. A. The mayor surveys 100 supporters at a rally

about the most important issues to be addressed by the city council.

The sample is biased. The supporters may have different ideas than those not at the rally.

B. The principal sends out questionnaires to all of the students to find out what kind of music students prefer at dances.It is not biased. The sample is random. The students all have a chance to respond.

Turn to page 414 and answer

2-3 and 6-7

Practice

The sample is random because ever customer has a chance to be picked for the 500.

The sample is biased because all city residents may not eat at this restaurant.

Practice

The sample is biased because listeners of the station are more likely to enjoy the music the station plays.

It is a random sample.

Dry Erase Board ActivityPopulations and Sample Review

Which better represents the population?

Suki’s method will better represent the school population because uses a random sample. Dinah’s method will produce results that are not as representative of the entire population because she uses a convenience sample.

Populations and Samples Review- Is the sample biased?

The sample is not biased because it is a random sample.

Populations and Samples Review- Is the sample biased?

The sample is biased. It is likely that not all high school students will choose the same kind of music as those who chosen by those who attended a jazz concert.

Which one is the population?

Which one is the better option?

Which one is not biased?

Random Sample?

yes

no

no

Biased sample?

yes

no

yes

Biased sample?

Yes because different passengers on other flights might feel differently

no

no

Yes because people at a movie might spend more/less then other people in the state

Work Session Complete the handout titled 7-8 Practice

C.

Read each question carefully and make sure you explain your answer.

Take your time.

Closing 1. When can a sample be biased?

2. Why is it important to use a random sample when looking at data?

Homework 7-8 Puzzles, Twisters, and Teasers

HomeworkWorkbook

page 65