3. The duration of time from rst exposure to coronavirus infection to a positive diagnosis is called the incubation period. The incubation periods of a random sample of 7 covid-19 infected individuals is given below [in days). (30 points] 12, 9.5, 13.5, 7.2, 10.5, 6.3, 12.5 a] Calculate the sample mean. b] Calculate the sample median. c] Calculate the sample standard deviation. d] If the number 6.3 above were changed to 1.5, what would happen to the sample mean, median, and standard deviation? State whether and why each would increase, decrease, or remain the same. You should be able to gure out the answer to these questions without doing any additional calculations, but you are welcome to do the calculations to check your answers