Can a low barometer reading be used to predict maximum wind speed of an approaching tropical cyclone? Data for this problem are based on information taken from Weatherwise (Vol. 46, No. 1), a publication of the American Meteorological Society. For a random sample of tropical cyclones, let x be the lowest pressure (in millibars) as a cyclone approaches, and let y be the maximum wind speed (in miles per hour) of the cyclone.

(a) Make a scatter diagram and draw the line you think best fits the data.
(b) Would you say the correlation is low, moderate, or strong? positive or negative?
(c) Use a calculator to verify that ˆ‘x = 5823, ˆ‘x2 = 5,655,779, ˆ‘y = 580, ˆ‘y2 = 65,750, and ˆ‘xy = 556,315. Compute r. As x increases, does the value of r imply that y should tend to increase or decrease? Explain.

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