A recent study suggests that that the number of steps walked per day is strongly associated with good health. A lower resting heart rate means that the heart is not working as hard to circulate blood in the body and may reduce the risk of heart attacks and stroke. A random sample of 10 adults between 35 and 40 years old was obtained and the number of steps taken per day (x, in thousands of steps - 1 = 1000 steps) was recorded. The next day, the resting pulse rate (y, beats per minute) for each person was also measured. The summary data is shown below:

n = 10, Σx = 46.239, Σx2 = 244.343, Σy = 698, Σy2 = 48784, Σxy = 3187.246, x̄ = 4.624, ȳ = 69.80

Required:
a. What are the assumptions that are required for simple linear regression?
b. Find the estimated regression line for the regression of pulse rate as a function of the number of steps (thousands) per day.