Correlation and Causality

Please use excel graph where necessary to answer 2 questions below include references.

Question 1.......

Crickets and Temperature. One classic application of correlation involves the association between the temperature and the number of times a cricket chirps in a minute. The scatterplot in Figure 7.7 shows the relationship for eight different pairs of temperature/chirps data. Estimate the correlation coefficient and determine whether there appears to be a correlation between the temperature and the number of times a cricket chirps in a minute.

Figure 7.7 Scatterplot for cricket chirps and temperature.

Source: Based on data from The Song of Insects by George W. Pierce, Harvard University Press.

(Bennett 246)

Question 2

Outlier Effects. Consider the scatterplot in Figure 7.15.

Figure 7.15

a. Which point is an outlier? Ignoring the outlier, estimate or compute the correlation coefficient for the remaining points.

b. Now include the outlier. How does the outlier affect the correlation coefficient? Estimate or compute the correlation coefficient for the complete data set.

(Bennett 254-255)

Bennett, Jeff, William Briggs, Mario Triola. Statistical Reasoning for Everyday Life, 4th Edition. Pearson Learning Solutions, 12/2012. VitalBook file.