The XO Group Inc. conducted a survey of brides and grooms married in the United States and found that the average cost of a wedding is (XO Group website, January , ). Assume that the cost of a wedding is normally distributed with a mean of and a standard deviation of:

Average cost is calculated in the following way

Explanation:

Given that XO Group Inc. conducted a survey of 13,000 brides and grooms married in the United States and found that the average cost of a wedding is $29,858

X is N(29,858, 5600)

Or Z=x-29158/5600 is N*(0,1)

We can use std normal distribution table to get the probabilities

a) The probability that a wedding costs less than $20,000 (to 4 decimals)

P(X<20000)

=0.039174

=0.0392

b) the probability that a wedding costs between $20,000 and $30,000

=0.5101-0.0392

=0.4709

c) For a wedding to be among the 5% most expensive, how much would it have to cost (to the nearest whole number)

=29858+1.645*5600

=38083