Numbeo.com collects data from users in cities around the world on prices of a basket of goods and services and uses these data to determine a cost of living index. This index scales New York City as 100 and expresses the cost of living in other cities as a percentage of the New York City cost. For example, in 2009, the cost of living index in Paris was

127.82,

which means that it cost

27.82%

more to live in Paris than New York City that year. The accompanying scatterplot shows the index for 2017 plotted against the 2009 index for

38

cities worldwide on which the website collected data in both years. Complete parts a through e below.

Cost of Living 2009	Cost of Living 2017
100.14	101.94
100	100
106.8	92.09
99.5	91.42
112.48	91.21
127.82	89.98
126.6	88.49
108.54	88.25
74.66	88.07
105.49	87.04
102.07	85.89
109.37	84.32
117.53	82.68
74.5	79.24
109.5	75.98
80.42	72.88
115.25	72.32
101.8	70.42
77.57	63.17
66.43	62.03
58.01	60.68
70.46	58.43
52.59	55.96
90.97	55.94
79.86	55.01
39.85	54.15
68.8	52.91
74.18	50.87
63.8	48.64
54.95	46.32
69.16	41.52
49.63	39.28
58.52	38.18
63.24	36.49
44.25	32.66
36.77	31.28
34.9	30.52
34.78	28.09
Cost of Living 2009	Cost of Living 2017

c) Find the correlation.

r=