1- An experiment was done to investigate the effects of two types of glass and the three types of phosphor on the current necessary (in microamperes) to obtain a specific brightness level of a television tube. The investigator decided to get three observations in each cell taken in order while the sequence of the six cells was decided randomly. The following data were obtained: Glass type Phosphor Type 1 2 280 230 1 275 840 240 705 1545 285 235 295 260 2 305 885 235 735 1620 285 240 265 230 3 280 820 215 665 1485 275 220 Yj 2545 2105 y...=4650 y.1=1560 Y-2=1550 Y.3=1540 a. Analyze the results using = 0.05. Do the phosphor type, glass type or their interaction have any effects on the current that determines television tube brightness level? b. b- Calculate the residuals of the experiment. Plot the residuals versus expected values of phosphor type and glass type. Comment on the adequacy of the model. c. Calculate R2 and comment on the result.