Hello; I have struggles to answer questions C and D of the following exercise (involving R code too). Could you explain to me how I have to solve this exercise? Is there a standard formula to use?

4. Using R? we tted a Studentt model to a sample of data which is stored in the vector Yi. The R code used for such task and some of the obtained results are as follows: 2 fit.t fit.t$n [1] 455 2 fit.t$estimate m s (11' [12028106 0.2095674 59.0414204 > fit.t$sd m 3 df [1010024465 [1008821197 90.988603748 2 fit.t$vcov m 3 df m 1.004899e04 4.762594e06 4107856965 s 4.782594e08 7.781352e05 [147418130 df 7.856965e02 4.741813e01 8278.92801173 {a} Compute an estimate of the variance of the model. (1)} Compute the Kurtosis estimate and comment the result. {c} Compute a 0.99 oondence interval for the degrees of freedom parameter. (d) Compute the correlation between the estimate of the scale and the shape parameters. {e} Compute the AIC value for the estimated model. Assume that the ADC value for a Gaussian model is 111.74. Which model is to be preferred? Solution {a} 0.045 (b) 3.109 (c) [1'."'5.'5f+3'1 293.413] (8} 0-591 {e} 189.831. The Gaussian model must he preferred