The amount of time a clay pot is in a kiln can be used to predict the number of impurities in the pot. Suppose the average time a clay pot is in a kiln is 32 minutes and the average number of impurities in clay pots is 10. Also suppose that the slope of a regression equation using the time a clay plot is in a kiln to estimate the number of impurities in the pot is b = 0.60. What is the value of the y-intercept, a?