A major credit card company has determined that customers charge between $100 and $1100 per month. If the monthly amount charged is uniformly distributed, a. The average charge would be. b. The standard deviation of the monthly amount charged would be .c. The percent of monthly charges between $600 and $889 would be .d. The percent of monthly charges between $311 and $889 is .

a)

b) First we need to calculate the variance given by this formula:

And the deviation would be:

c)

And using the cdf we got:

d)

Step-by-step explanation:

For this case we define the random variable X who represent the customers charge, and the distribution for X on this case is:

Part a

For this case the average is given by the expected value and we can use the following formula:

Part b

First we need to calculate the variance given by this formula:

And the deviation would be:

Part c

For this case we want to find the percent between 600 and 889, so we can use the cumulative distribution function given by:

And we can find this probability:

And using the cdf we got:

Part d

And using the cdf we got:

answer: graph 2

step-by-step explanation: