MS 150 Statistics Quiz 04 • Name:

04 February 2011

A drought in West Africa and political instability in Côte D'Ivoire, producer of 40% of the world's cocoa beans, has led to dramatic price rises for chocolate. The table tracks the price in United States dollars per tonne from September 2010 (month 1 in the table) to February 2011 (month 6 in the table; February price based on the daily price per tonne at the start of the month). Data from the International Cocoa Organization. See also:
World Chocolate Shortage ahead?
World Chocolate Supply in Decline?
Could Ivory Coast turmoil make chocolate more expensive?
Cocoa bean prices soar as world faces chocolate drought

1. ______________ Determine the slope of the linear regression for the data.
2. ______________ Determine the y-intercept of the linear regression for the data.
3. ______________ Extrapolating beyond the maximum x value is not usually statistically valid. Despite this, use the linear regression to predict the price per tonne for chocolate in month 7 (equivalent to March 2011).
4. ______________ Extrapolating beyond the maximum x value is not usually statistically valid. Despite this, use the linear regression to predict the month number in which the price is predicted to reach $4000 per tonne.