Question 842552
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Hi,
Note: The probability of x successes in n trials is: 
P = nCx* {{{p^x*q^(n-x)}}} where p and q are the probabilities of success and failure respectively. 
In this case p(carry either a cell phone or a laptop) = .8 & q = .2  and  n = 15
A)what are the possible values of the number of business travelers carrying a cell phone or a laptop in the sample? 
 0 &#8804;  x  &#8804;   15
B)What is the expected number of business travelers carrying a phone or a laptop in such a sample? {{{.8*15 = 12}}}
C) Is this probability distribution skewed to right or left?
Note:  distributions with fewer observations on the left (toward lower values) are said to be skewed left.
D)Compute the standard deviation of the number of business travelers carrying a phone or a laptop in such a sample. {{{sqrt(15*.8*.2)}}}
E)What is the probability that exactly 8 business travelers in a sample carry a cell phone or a laptop?
TI Calculator: binompdf(n, p, x-value) = binompdf(15, .8,8) 
F)What is the probability that 7 of the 15 business travelers have neither a cell phone nor a laptop? binompdf(15, .2,7) 
G)What is the probability that at least 10(ten) business travelers in the sample have a cell phone or a laptop? 
1 – binomcdf(n, p, largest x-value)= 1 – binomcdf(15, .8, 9)