3. The R code below provides a NIST data set concerning the absorption of moisture by concrete depending on the weight percentage of a key (unknown to me) ingredient d <- data.frame(weight_percent-rep(1:5,each-6), moisturec(551,457,450,731,499,632, 595,580,508,583,633,517, 639,615,511,573,648,677, 417,449,517,438,415,555, 563,631,522,631,656,679)) a) Construct a plot of moisture vs weight percent. Based solely on the plot, discuss which of the following models are the most reasonable: intercept only, linear in weight percent, quadratic in weight percent, or each weight percent
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