Ms. Drake 7th grade Math Measures of Central Tendency Lesson 1 Populations and Samples

Measures of Central Tendency Vocabulary Bar graph Box- and-Whisker Plot Circle Graph Cumulative Frequency Double Bar Graph First Quartile Frequency Table

Measures of Central Tendency Vocabulary Histogram Line Graph Lower Extreme Mean Median Mode Negative Correlation No correlation

Measures of Central Tendency Vocabulary Outlier Population Positive correlation Random Sample Range Sample

Measures of Central Tendency Vocabulary Scatter Plot Second Quartile Sector Stem-and-Leaf Plot Third Quartile Upper Extreme

Chapter 1 Populations and Samples Population: The entire group of objects or individuals considered for a survey Samples: A part of the population

All elementary students make up a population. Students from this particular class are the sample.

Examples Population: All lions Sample: Lions in a game preserve.

Example Population: All customers Sample: The customers who fill out a survey

Identify the Population and Sample in Each Situation The decoration committee asks 25 students about their ideas for a 7 th grade party.

The population is the 7th grade. The sample is the 25 students surveyed.

Identify the population and the sample in this situation. A disc jockey asks the first ten listeners who call in if they like the last song that was played.

The population is all the listening public. The sample is the first ten listeners

Identify the population and the sample in this situation. Researchers poll every fifteenth voter after a local election.

The population is all the people who voted. The sample is the fifteen voters that were polled.

Random Sampling For a sample to be useful, it must represent the population. A random sample gives every member of the population an equal chance of being chosen.

The local grocery store wants to know if their customers are satisfied with their service..

The manager surveys the customers that he knows personally Tell whether each sampling method is random:

The manager surveys every tenth customer that comes into the store on Friday morning.

Tell whether each sampling method is random: The manager puts the names of all customers in a hat and surveys the customers whose names he draws.

Give a reason why each sampling method may not be random. A reporter calls 100 people from the telephone book.

A researcher questions all of the customers at one of several entrances to a supermarket. Give a reason why each sampling method may not be random.

A reporter surveys people who are using an internet site

Until next time, try to come up with some other ways that you can use what you know about populations and samples.