Hi,





Note: The probability of x successes in n trials is: 

P = nCx* * where p and q are the probabilities of success and failure 

respectively. In this case  p(late) = .2 and q = .8

nCx = 



A. Find the probability that the student will be late exactly 5 times.

P = 30C5* *



B. Find the probability that he will be late fewer than 3 times.

P( 0 lates) + P(1 lates) + P(late twice)



C. Find the average number of times he will be late. 

Mean = n*p = 30*(.2) = 6 times

D. Find the standard deviation of the number of times he will be late.

Definition of standard deviation =  =  

Answer by Fombitz(32388)   (Show Source): You can put this solution on YOUR website!
 n=30

p=0.8

q=0.2

.

.

.

A) 

.

.

B) 







.

.

C) Using EXCEL's BINOMDIST to generate all of the probability values from 0 to 30, then summing ,



or 



.

.

D) Again using EXCEL's BINOMDIST, the result from C), and then summing.







or

 

RELATED QUESTIONS

A student is known to arrive late for a class 40% of the time. If the class meets five... (answered by stanbon,ewatrrr)

There are 1000 students in the senior class at a certain high school. The high school... (answered by stanbon)

In a statistics class there 30 females and 20 males; 18 of the females are freshmen and... (answered by fractalier)

Suppose the number of students in a class for the Business Statistics program at a... (answered by jim_thompson5910)

In a statistics class there are 30 females and 20 males; 18 of the females are freshmen... (answered by fractalier)

A university has 14 statistics classes scheduled for its Summer 2013 term. One class has... (answered by math_tutor2020)

What is the formula for this problem:

A class contains 10 students enrolled in JAVA... (answered by solver91311)

An elementary school is offering two optional language classes, one in French and the... (answered by ikleyn)

5. There are 15 males and 10 females in a statistics class. If one student is chosen at... (answered by jim_thompson5910)