Question 6.66

image 31. Exercise 11, Table 6.8 (page 280) presented data on fish length and mercury concentration in fish tissue.

  1. If you did not do so in Exercise 11, make a scatterplot of mercury concentration against fish length. Based on your scatterplot, would you expect the correlation between these two variables to be positive or negative? Explain.
  2. Using either your calculator or spreadsheet software such as Excel, calculate the correlation between mercury concentration and fish length (refer to Spotlight 6.2). Using the guidelines in Figure 6.10 (page 255), classify the strength of the linear relationship as strong, moderate, or weak.

31.

(a) Correlation is positive because the association between fish length and mercury concentration in fish tissue is positive.

(b) ; there is a strong linear relationship between these two variables.