Question

1.Suppose the round-trip airfare between Boston and Orlando follows the normal probability distribution with a mean of $387.20 and a standard deviation of $68.50. What is the probability that a randomly selected airfare between Boston and San Francisco will be more than $450?

0.0788

0.3369

0.2033

0.1796

2.Suppose the round-trip airfare between Boston and Orlando follows the normal probability distribution with a mean of $387.20 and a standard deviation of $68.50. What is the probability that a randomly selected airfare between Boston and San Francisco will be less than $300?

0.3192

0.2005

0.4286

0.1015

Answer 1

Solution :

Given that ,

1) mean = = 387.20

standard deviation = = 68.50

P(x > 450) = 1 - p( x< 450 )

=1- p [(x - ) / < (450 - 387.20) /68.50 ]

=1- P(z < 0.92 )

= 1 - 0.8204 = 0.1796

probability = 0.1796

Answer = 0.1796

2)

P(x < 300 ) = P[(x - ) / < (300 -387.20) /68.50 ]

= P(z < -1.27 )

= 0.1015

probability =0.1015

Answer = 0.1015