The value ofY, the percentage decrease of volume of leather from the value at one atmosphere pressure, was measured for certain fixed values of high pressure,xatmospheres. The relevant data about the relationship are as follows:
∑x= 28,000, ∑y= 19.0, ∑xy= 148,400, ∑x
2 = 216,000,000, ∑y
2 = 102.2,n= 4.
a) Find the regression line ofyonx.
b) Find the correlation coefficient between decrease of volume and pressure.
c) Assuming that graphical checks are satisfactory:
i) Test whether the slope of the regression line is significantly different from zero at the 1% level of significance.
ii) Find the 99% confidence limits of the slope of the regression line.