Tosca University estimates the probability that a randomly chosen Tosca-U student would have COVID19 to be: p = 0:06. This probability can be assumed to remain fixed from student to student, independent of whether another student in the class had COVID. The University has asked you to determine the following (for each question be sure to specify what probability model you are using and justify the choice.)

(a) (2 points) The probability that the first COVID19 positive student will be the 4th

student to enter the classroom.

(b) (1 point) On average how many Tosca-U students would be examined so as to

encounter the first COVID-positive student.

(c) (2 points) The probability of more than 17 negatives in a class size of 21 students.

(d) (1 point) The standard deviation, of the number of positives in a class of 21 students.

(e) (2 points) The probability that the first positive encountered is in one of the first

4 students.