Question

Slader the internal revenue service claims it takes an average of 3.7 hours to complete a 1040 tax form, assuming th4e time to complete the form is normally distributed witha standard devait of the 30 minutes:

a. What percent of people would you expect to complete the form in less than 5 hours?
b. What time interval would you expect to include the middle 50 % of the tax filers?

Answer 1

0.9953, 3.3629<x<4.0371

Explanation:

Given that slader the internal revenue service claims it takes an average of 3.7 hours to complete a 1040 tax form, assuming th4e time to complete the form is normally distributed witha standard devait of the 30 minutes:

If X represents the time to complete then

X is N(3.7, 0.5) (we convert into uniform units in hours)

a) percent of people would you expect to complete the form in less than 5 hours

=
`100*P(x<5)\\= 0.9953`

b) P(b<x<c) = 0.50

we find that here

c = 4.0371 and

b = 3.3629

Interval would be

`(3.3629, 4.0371)`