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Chapter 3: Q 27. (page 174)

Correlation isn鈥檛 everything Marc and Rob are both high school English teachers. Students think that Rob is a harder grader, so Rob and Marc decide to grade the same 10 essays and see how their scores compare. The correlation is r=0.98 but Rob鈥檚 scores are always lower than Marc鈥檚. Draw a possible scatterplot that illustrates this situation.

Short Answer

Expert verified

The highest possible score is 100%

Step by step solution

01

Given information

Correlation,r=0.98

02

Explanation

Rob鈥檚 scores are always lower than Marc鈥檚.

A positive linear correlation exists when r is positive.

A negative linear correlation exists when r is negative.

For weak correlation,

0<|r|<0.5

For moderate correlation,

0.5<|r|<0.8

For strong correlation,

0.8<|r|<1

Note that

The correlation between Rob's and Marc's scores is significant and positive.

Since the data involves the same 10essays for both the teachers.

Moreover,

The points should be properly aligned in a straight upward-sloping line.

However,

Ascertain that Rob's scores are consistently lower than Marc's.

Assume that

Scores were in percentage.

Thus, The highest possible score is 100%

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