The sea ice extent is the area of the ocean with at least 15% sea ice. The association between years since 1970 and the mean sea ice extent in the northern hemisphere in March is described by the scatterplot in Fig. 69. The association between years since 1970 and the mean sea ice extent in the northern hemisphere in September is described by the scatterplot in Fig. 70.

a. Is there a positive association, a negative association, or no association between the years since 1970 and March sea ice extent? What does that mean in this situation?
b. Is there a positive association, a negative association, or no association between the years since 1970 and September sea ice extent? What does that mean in this situation?
c. Estimate the mean loss of sea ice extent from March to September for the period 1979€“2013.
d. The association between years since 1970 and the difference in sea ice extent in March and September is described by the scatterplot in Fig. 71. Does the scatterplot check with your response to part (c)? Explain.
e. The association between the sea ice extent in March and the sea ice extent in September is described by the scatterplot in Fig. 72. Is there a positive association, a negative association, or no association? What does that mean in this situation? Explain how this connects to your responses to parts (c) and (d).

Transcribed Image Text:

Years versus March Ice 16.5 16. 15.5 15 14.5 14 13.5 5 10 15 20 25 30 35 40 45 Years since 1970 Years versus September ice 7. 5 10 15 20 25 30 35 40 45 Years since 1970 Years versus Difference in Ice Extent E 11 10 5 10 15 20 25 30 35 40 45 Years since 1970 March Ice versus September Ice 13.5 14 14.5 15 155 16 16.5 March ice (millions of square kilometers)