By using language R, the data set missiles.txt presents the test-firing results for 25 surface-to-air antiaircraft missiles at targets of varying speed. The result of each test is either a hit (y = 1) or a miss (y = 0).

speed y 400 0 220 1 490 0 210 1 500 0 270 0 200 1 470 0 480 0 310 1 240 1 490 0 420 0 330 1 280 1 210 1 300 1 470 1 230 0 . 0 460 0 220 1 250 1 200 1 390 0 

(a) Read in the data as a data frame. After that you will find that the speed of the 20th observation is missing. Fill in this missing entry with 430. Make sure the variables have the correct types.

(b) Fit the logistic regression model with speed as the only predictor. Use the summary function to print the results. Is the predictor significant?

(c) Repeat the previous part using LDA.

(d) Repeat the previous part using kNN.

(e) In terms of the classification accuracy, which of these methods appears to provide the best results on this data? Explain why.