Question
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The following figure shows a scatterplot. Which of the following statements are correct?
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![](scatterplot-1.svg)
Answerlist
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* The absolute value of the correlation coefficient is at most $0.8$.
* The standard deviation of $X$ is at least $6$.
* For $X = 17.1$, $Y$ can be expected to be about $19.9$.
* The scatterplot is standardized.
* The mean of $Y$ is at least $30$.
Solution
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Answerlist
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* False. A strong association between the variables is given in the scatterplot. Hence the absolute value of the correlation coefficient is close to $1$ and therefore larger than $0.8$.
* True. The standard deviation of $X$ is about equal to $20$ and is therefore larger than $6$.
* True. The regression line at $X=17.1$ implies a value of about $Y = 19.9$.
* False. The scatterplot is not standardized, because $X$ and $Y$ do not both have mean $0$ and variance $1$.
* False. The mean of $Y$ is about equal to $20$ and hence is smaller than $30$.
Meta-information
================
extype: mchoice
exsolution: 01100
exname: Scatterplot