Skin cancer prevention trial. The data in the file skincancer.dat on the course webpage are from a clinical trial to study the effectiveness of beta-carotene to prevent non-melanoma skin cancer in high risk subjects with previous skin cancer. The data are from m = 811 subjects recruited from 4 medical centers who were randomized to 50 mg beta-carotene per day (coded as 1) or placebo (coded as 0), each of whom miraculously returned to the clinic at years 1, 2,3, 4, and 5 after starting on his/her assigned treatment. Several baseline variables were collected, as shown below; the variable exposure is a count of the number of previous skin cancers experienced by each subject at baseline. The outcome is the binary indicator of presence of skin cancer. The data set has the following columns: 1 subject ID 2 center (1, 2, 3, 4) 3 age at baseline (years) 4 skin type (1 = burns, 0 = no burns) 5 gender (0 = female, 1 = male) 6 7 exposure presence of skin cancer (outcome, 0 no, 1 - yes) 8 treatment (0-placebo, 1 9 year (1, 2, 3, 45) beta-carotene) The investigators are interested in the following questions: (i) Is there evidence that the probability of new skin cancers changes from baseline over the study period for either treatment? (ii) Does beta-carotene lead to a lower probability of new skin cancers than placebo after five years in this population? (iii) What is the probability of experiencing new skin cancers at year 5 for each treatment? (iv) Is there evidence that the probability of experiencing new skin cancers over the study period is associated with age, gender, previous cancer (exposure), or center? Using methods in the notes, carry out analyses to address these questions. State the models and describe how you formalized the questions of interest within the framework of these models and interpret the results in the context of the subject matter. (Use can use SAS, R, or Python) Dataset & Notes can be found here: https://drive.google.com/drive/folders/1pgV4RfrhnPBeqvqMZv ekwwJaTUCRIZV9?usp=sharing