Need help understanding what i have done wrong with part 2

Part 1 = you have joined the university system in New Zealand.This system has a financial form that they use for their students.Many students have complained of mistakes on this form.You have been hired in to develop some qualitycontrols for the system and to improve the quality level.You plan to start with a simple easy to understand p chart.The p-chart monitors the proportion of nonconforming forms.You have set a fixed sample size of 40 forms per day to examine.The number of non-conforming (defective units) is as follows:

Day. Defective Bills

1 16

2 15

3 19

4 15

5 20

6 15

7 19

8 18

9 19

10 19

11 17

12 18

13 18

14 17

15 16

16 16

17 18

18 20

19 18

20 14

21 18

22 22

23 17

24 23

Use the p-chart software and answer the following questions.

What is your sample size? (whole number)

What is the number of samples that you took? (whole number)

What is the average p-bar? Blank 3(four decimals)

From your sample what proportion of financial forms are defective?B(two decimals)

Looking at your associated graph, is the process in control?(yes or no)

Does it appear to be "heading in the wrong direction"? (yes, no,cannot tell)

I submitted the following and it was 100% correct:

a)40

b)24

c) 0.4448

d)0.44

e) yes

f) yes

Taking the data from part 1 i moved on to part 2

Part 2 = You have improved the process by placing the form on a computer and checking

the inputs for correctness.With this change you feel that you have made a

significant (above statistical chance)improvement.You have run 25 sub groups of

40 each.But first what is the confidence interval for what you had orginallydone.

Using a 99 percent confidence level what are the the low and high value for the confidence

interval.For the original situation, answer the following two questions.

The proportion low value is?(Three decimals)

The proportion high value is?(Three decimals)

my answers were as follows:

a) 0.413

b) 0.477

They keep telling me its wrong but i don't understand why its wrong. Help with Part 2 of the problem.