Using the same data given in 8-32, the researcher calculates the partial autocorrelation functions that given below:

(i) What do you mean by the sample partial autocorrelation function? Why is the first partial autocorrelation equal to the first autocorrelation coefficient (0.78)?
(ii) Does the above pattern indicate that an AR or MA process is more appropriate? Why?

K -0.03 9 -0.01 1 2 3 4 6 8 0.78 0.15 -0.10 0.06 0.04 -0.05 0.09