AP Statistics : How to interpret dotplots

Study concepts, example questions & explanations for AP Statistics

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Example Questions

Example Question #1 : Graphing Data

A basketball coach wants to determine if a player's height can be used to predict the number of points that player scores in a season.  Before using a statistical test to determine the precise relationship of the variables, the coach wants a visual of the data to see if there is likely to be a relationship.  Which of the following should the coach create?

Possible Answers:

Histogram

Bell curve

Scatterplot

Z-score

Bar chart

Correct answer:

Scatterplot

Explanation:

A scatterplot is a diagram that shows the values of two variables and provides a general illustration of the relationship between them.

Example Question #2 : Graphing Data

Based on the scatter plot below, is there a correlation between the  and  variables? If so, describe the correlation.

Question_11

Possible Answers:

Yes; positive linear relationship

No; there is no correlation

Yes; negative linear relationship

Yes; negative exponential relationship

Correct answer:

Yes; negative linear relationship

Explanation:

The data points follow an overall linear trend, as opposed to being randomly distributed. Though there are a few outliers, there is a general relationship between the two variables.

A line could accurately predict the trend of the data points, suggesting there is a linear correlation. Since the y-values decrease as the x-values increase, the correlation must be negative. We can see that a line connecting the upper-most and lower-most points would have a negative slope.

An exponential relationship would be curved, rather than straight.

Example Question #1 : How To Interpret Dotplots

Order the correlation coefficients to fit the order of the following graphs (two coefficients will not be used)

,  , ,  ,  

Scattertot

Possible Answers:

,  ,  

,  ,  

, ,

, ,

, ,

Correct answer:

, ,

Explanation:

The first graph is random scatter, no correlation, the second is perfect linear, corellation , the last two have fairly strong positive and negative corellations, the student should know that a corellation of  is much weaker than them

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