Stock brokers and even casual investors are always searching for better methods to predict the movement in the price of stocks. The “skirt-length theory” suggests that if women’s skirts are short,...

Stock brokers and even casual investors are always searching for better methods to predict the movement in the price of stocks. The “skirt-length theory” suggests that if women’s skirts are short, then the markets will rise. If skirts are long, then the markets will be headed down. To test this theory, a random sample of years was obtained, and the length of women’s skirts was measured (x, in inches) for a typical fashion model. The change in the S&P 500 market index ( y) was also recorded for that year. The data are given in the following table.