scatter plots and correlations

Scatter Plots and Correlations

Is there a relationship between the amount of gas put in a car and the number of miles that can be driven?

Positive Correlation

As one set of data values increases, so does the other.

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Positive Correlation

Is there a relationship between the number of things you buy at the mall and the amount of money you have left?

Negative Correlation

As one set of data values increases, the other decreases.

Negative Correlation

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Is there a relationship between a person’s age and the temperature outside?

No Correlation

There is no relationship between the two sets of data.

No Correlation

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Would a scatter plot show a positive,negative, or no

correlation?Number of pages printed by a printer and the amount of ink left in the cartridge.– Negative Correlation!

Would a scatter plot show a positive,negative, or no

correlation?

Age of a child and the child’s shoe size– Positive Correlation!

Would a scatter plot show a positive,negative, or no

correlation?Number of letters in a person’s first name and the person’s height.– No Correlation!

Would a scatter plot show a positive,negative, or no

correlation?

Shots attempted and the number of points made in a basketball game– Positive Correlation!

Would a scatter plot show a positive,negative, or no

correlation?

Length of a taxi ride and the amount of the fare– Positive Correlation!

Would a scatter plot show a positive,negative, or no

correlation?

Outside temperature and the cost of air conditioning.– Positive Correlation!

Would a scatter plot show a positive,negative, or no

correlation?

Miles ridden on a bicycle and the thickness of the tire tread– Negative Correlation!

Would a scatter plot show a positive,negative, or no

correlation?

Temperature outside and the amount of clothing a person wears– Negative Correlation!

Think of some situations that show a….

Positive Correlation:

Negative Correlation:

No Correlation:

Which graph to use…..?

Use bar graphs to make comparisons.Use line graphs to show change over time.Use circle graphs to show percentage of a whole.Use histograms when the data is arranged in intervals.Use scatter plots to show correlations between two sets of numerical data.

In a company there are 10 employees who each make $10,000 per year. The boss makes $80,000 per year. A job recruiter tells applicants that the average salary at the company is $16,364.

Is this misleading?

Using the appropriate measure of central tendency

Which measure of central tendency did the job recruiter use?

Which measure of central tendency should he have used?

Use the mean when the data values are close together.Use the median when there are large gaps in the data values.Use the mode when looking for the most common outcome.

What measure of central tendency to use?