A fair coin is tossed 8 times and the number of heads observed. The probability that exactly 3 heads will be observed is?

22%

19%

27%

15%

What is the standard deviation of a Binomial distribution of survivors of a disease with a survival rate of 70% for a sample of 50 patients.

5.9

10.4

3.24

7

What is the mean of a Binomial distribution of survivors of a disease with a survival rate of 70% for a sample of 50 patients.

7

35

50

3.5

In a course, based on historical data 15% of the students fail. What is the best estimate for the standard deviation for number of students failing in the next semester if 35 students will be taking the class?

3.25

1.25

2.1

4.46