Probability Problem

[Sarma]

I have this problem in probability that defies me and I need the help of Access experts.

I have a query which provides probability of occurrences for items A,B,C,D below 5, 10, 15 and 20.

Yet another query gives probability of occurrences for items A,B,C,D above 5,10,15 and 20.

Now I need the combined probability for each of the items A,B,C,D.

Please help me with the SQL.

What is available and what is needed are both attached.

Regards

 

[Sarma]

It is necessary to have the 2nd and 3rd columns too; in the output. So that the output has the format Item-Probability below-Probability above-Combined probability,

 

[Sarma]

I think that there would be 3 SQLs in this case. The first one and the second one will limit the query 1 and query 2 to 2 columns. Third one will be made using the output from the first 2 SQLs.

 

[Sarma]

Perhaps, the first SQL will result in 16 rows and 2 fields. (Item-BelowValueFreq)

The second SQL will result in 16 rows and 2 fields. (Item-AboveValueFreq)

The third SQL will result in 256 rows and 4 fields. (Item-BelowValueFreq-AboveValueFreq-CombinedValueFreq)

 

[gemma-the-husky]

I do not quite understand the substance of the probability

do the two tests not add to 100%, in which case result2 is (1 - result1)

if not, can you explain more clearly what the tests do.

 

[Sarma]

GEMMA: Yes, the freq above and below add up to the same number i.e. the total number. But in order that both the events should happen together, simultaneously, the combined probabability would be the product of individual probabilities. I have re-arranged the numbers suitably now.

First SQL will have 3 fields and 16 rows. 2nd SQL will also have three fields and 16 rows. 3rd SQL which is the answer will have 4 fields and 256 rows.