According with the IRS the taxpayers spent an average of 330 minutes in preparing, copying and to file in an electronic way the fiscal form 4020. An organization that watches over the consumers it selects a chance sample of 40 taxpayers and finds that the time needed to prepare, to copy and to file the form 4020 is 80 minutes.

a) Which is the standard error of the median in this example?

b) Which is the probability of that the median of the sample or average medians is greater or more than 320 minutes?

c) Which is the probability of that the median of the sample or average medians be between 320 and 350 minutes?

d) Which is the probability of that the average or median of the sample is greater than 350 minutes?