Ch 4B

CH 4B SCATTERPLOT And CORRELATION Example 1 I wish to determine the correlation between the height (in inches) and weight (in pounds) of 21 year old males. To do this, I measure the height and weight of two 21 year old men. The measured values are: Male #1 Male #2 Height 70 69 Weight 160 164 The correlation 𝑟 computed from the measurements on these males is: a. 1.0. b. near 0, because the heights and weights of the men are similar. c. -1.0. Example 2 A statistics student computes the correlation between two variables in her spreadsheet and finds 𝑟 =0.06. She concludes there is no relationship between the variables. Is she correct? a. yes b. We do not have enough information to answer the question. c. no Example 3 A recent article in an educational research journal reports a correlation of +0.8 between math achievement and overall math aptitude. It also reports a correlation of −0.8 between math achievement and math anxiety. Which of the following interpretations is the most correct? a. The correlation of +0.8 is just as strong as the correlation of −0.8. b. It is impossible to tell which correlation is stronger. c. The correlation of +0.8 indicates a stronger relationship than the correlation of −0.8.
Example 4 Which plot indicates a correlation of 0.7? a. b. c.
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