please help with the ones not answered thank you A particular article proposed a quadratic regression model to describe the relationship between x = degree of delignification during the processing of wood pulp for paper and y = total chlorine content. Suppose that the actualmodel is the following.165+752-4r²+c(a) Mean chlorine content for x = 6 is lower than ✔✔✔ mean chlorine content for x = 8.(b) What is the change in mean chlorine content when the degree of delignification increases from 6 to 7?What is the change in mean chlorine content when the degree of delignification increases from to 14?33x The relationship between yield of maize, date of planting, and planting density was investigated in an article. Let the variables be defined as follows.y = percent maize yieldx = planting date (days after April 20)z = planting density (plants/ha)The following regression model with both quadratic terms where x₁ = x, X₂ = 2, x3 = x² and x4 = 2² provides a good description of the relationship between y and the independent variables.y = a +3₁x₂ + Brzy + Były + Baixa +c(a) Ir a = 21.07, B₁ = 0.653, ₂ = 0.0022, B3 = -0.0207, and B4=0.00002, what is the population regression function?y = 21.07+0.653x +0.0022z-0.0207x²+0.000022²X(b) Use the regression function in Part (a) to determine the mean yield for a plot planted on May 7 with a density of 41,182 plants/ha. (Give the exact answer.)(c) Would the mean yield be higher for a planting date of May 7 or May 23 (for the same density)?The mean yield would be higher for May 7You may need to use the appropriate table in Appendix A to answer this question.Additional Materialn

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A particular article proposed a quadratic regression model to describe the relationship between x = degree of delignification during the processing of wood pulp for paper and y = total chlorine content. Suppose that the actual model is the following. y-165+75-4²+ (a) Mean chlorine content for x = 6 is lower than mean chlorine content for x = 8. (b) What is the change in mean chlorine content when the degree of delignification increases from 6 to 77 23 What is the change in mean chlorine content when the degree of delignification increases from 13 to 14? 33