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You're thinking of starting a leggings business and need to predict how many leggings will be sold, based on sales in the first three months of the year. The data are shown in the table below. month 1 2 3 leggings sold (millions) y 15 30 50 (a) Calculate the ordinary least squares best-fit line of the form y = ax + 6, where a is the month and y is the number of leggings sold (in millions). What are the values of a and b? Give your answer as decimals written to two decimal places. a= b= (b) What is the predicted sale of leggings (in millions) y for month 4? Give your answer as a decimal written to two decimal places. y= (c) What is the residual 7 for month 1? Give your answer as a decimal written to two decimal places. r=