Ms. Drake 7th grade Math

Measures of Central Tendency

Lesson 1Populations and Samples

Measures of Central Tendency Vocabulary

Bar graphBox- and-Whisker PlotCircle GraphCumulative FrequencyDouble Bar GraphFirst QuartileFrequency Table

Measures of Central Tendency Vocabulary

HistogramLine GraphLower ExtremeMeanMedianModeNegative CorrelationNo correlation

Measures of Central Tendency Vocabulary

OutlierPopulationPositive correlationRandom SampleRangeSample

Measures of Central Tendency Vocabulary

Scatter PlotSecond QuartileSectorStem-and-Leaf PlotThird QuartileUpper Extreme

Chapter 1

Populations and SamplesPopulation: 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 lionsSample: Lions in a game preserve.

Example

Population: All customersSample: 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 7th 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:

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.