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## #1 Help Me ! » Confidence Intervals » 2005-11-28 07:41:48

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I'm really stumped on this question!

I've been asked to calculate the confidence intervals for the value of time calculated when the size is equal to : 3 time standard deviation.

Here is the data i've been given.

Time(h) Size(mm)
1        9.7
2        9.7
3        9.8
4        9.8
5        9.8
6        9.9
7        9.9
8        9.9
9        9.9
10       9.9
11      10.1
12      10.1
13      10.1
14      10.2
15      10.2
16      10.2
17      10.3
18      10.3
19      10.4
20      10.5

## #2 Help Me ! » Probabilty / Empirical and theoretical » 2005-11-28 07:39:39

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I'm struggling on some questions about probabilty.

I've got a table with Failure in days and frequency.

Failure (Days) Frequency
12 to 14         1.00
15 to 17        15.00
18 to 20        60.00
21 to 23        83.00
24 to 26       108.00
27 to 29        76.00
30 to 32        45.00
33 to 35        16.00
36 to 38         1.00

So theres the data, right...

I've been asked to work out :-

a) The probabilty of failure for components between 0 days and 19 days.

b) Probabilty of the component failing between 19 and 31 days.

I've got to use two methods empirical and theoretical to determine the probability distrubtion and then show how confident these answers are going to be when compared against each other.

Also i've got to produce a graph in excel that shows all this, is that possible?