13-9. Go Tutorial An electronics engineer is interested in the effect on tube conductivity of five different types of coating for cathode ray tubes in a telecommunications system display device. The following conductivity data are obtained. Conductivity Coating Type 1 143 141 150 146 2345 2 152 149 137 143 134 133 132 127 4 129 127 132 129 5 147 148 144 142 (a) Is there any difference in conductivity due to coating type? Use α=0.01. (b) Analyze the residuals from this experiment. (c) Construct a 95% interval estimate of the coating type 1 mean. Construct a 99% interval estimate of the mean dif- ference between coating types 1 and 4.