Consider the following sample data for the variables y and x:

a. Calculate the linear regression equation for these data.
b. Determine the predicted y -value when x = 10.
c. Estimate the change in the y variable resulting from the increase in the x variable of 10 units.
d. Conduct a hypothesis test to determine if an increase of 1 unit in the x variable will result in the decrease of the average value of the y variable. Use a significance of 0.025.