Question

Hi, I found the percentages the questions asked for but I am not sure how to create a line distribution graph with $3333 as the mean in Excel. Any help on how to make the graph in Excel would be much appreciated, thanks.

According to the IRS the mean tax refund for the year 2009 was $3333                                                                                                                                

The standard deviation of the population of returns is $551, and the amounts follow the normal distribution                                                                 

              Using Norm.Dist                                                                                                                  

a            What percent of the returns are more than $2000?                                                                                                               99.22%                                                                                                                           

b            What percent of the returns are more than $5000?                                                                                                               0.12%                                                                                                               

c.           What percent of the returns are between $3000 and $5000?                                                                                                                                                                                                                                          72.60%                                                                                                        

Create an approximate line graph of this normal distribution with $3333 as the mean                                                                           

You can make a table of values from which to create the graph

Answer 1

Solution-A:

X~N(3333,551)

P(X>2000)

=1-P(x<2000)

iN EXCEL for P(X<2000)

=NORM.DIST(2000,3333,551,TRUE)

=0.007776536

So

=1-0.007776536

=0.992223464

=0.992223464*100

=99.22%

Solution-b:

P(X>5000)

=1-P(X<5000)

=1-{=NORM.DIST(5000,3333,551,TRUE)}

=1-0.998758512
=0.001241488

=0.001241488*100

=0.12%

0.12%

Solution-c:

P(3000<X<5000)

P(x<5000)-P(X<3000)

==NORM.DIST(5000,3333,551,TRUE)-=NORM.DIST(3000,3333,551,TRUE)

0.998758512-0.272803585

= 0.7259549

= 0.7259549*100

=72.6%