There are 50 students in our class. (1) What is the probability that Jack and Mike have the same birthday? (2) What is the probability that no one has the same birthday as the professor? (3) What is the probability that there are two and only two having the same birthday?

1) 0.00274

2) 0.872

3) 0.00240

Step-by-step explanation:

1) 365/(365×365) = 1/365

= 0.002739726027

= 0.00274 (3 sf)

2) (364/365)^50

= 0.8718182573

= 0.872 (3 sf)

3) [365 × (364^48)]/(365^50)

= 0.002401685062

= 0.00240 (3 sf)

4.66 pounds

Step-by-step explanation:

follow the following steps to calculate the standard deviation :

1. find the mean of the observations

2. subtract the mean from each observations

3. square the result gotten from the answers gotten in the previous step

4. Add each of the squares gotten above and divide by the number of observations

5. find the square root of the answer gotten in the above stage

check the attached images for an explanation of how the answer was derived.