For the data used in Exercise 11, RAN1T1 and RAN2T1 (stored in columns 4 and 5) are measures of digit-naming speed and letternaming speed, respectively. Use M regression with Schweppe weights to...

For the data used in Exercise 11, RAN1T1 and RAN2T1 (stored in columns 4 and 5) are measures of digit-naming speed and letternaming speed, respectively. Use M regression with Schweppe weights to estimate the regression parameters when predicting WWISST2. Use the function elimna, described in Chapter 1, to remove missing values. Compare the results with the OLS estimates and βˆ
_ch.