question:how to check data

[rainyfree]

Recently I had some interviews. I got a common question:
how do u do with the data(or check whether the data is correct) before you do the analysis or regression?

My answer is : plot the gragh of the data to see whether the distribution and the trend is reasonal, and calculate the descriptive statistics.

I am not sure whether this way is feasible. Please let me know your methodology and suggestions. I look forward to your reply.

Cheers.

[GaryMazzone]

Please don't double post.

I would take that to mean before posting to the DB is the data correct on the page? In that case I would attempt to apply the Bussiness rules to test if all required data is present on the form, is all the data of the correct type? Then do the post to DB.

[Dnereb]

I ussally check data on input to check if it is within scope.
and just disallow invalid keystrokes. i.a.w. You couldn't type letters in a textbox if it should be a number etc...
This greatly simplify's more intelligent data checks like is it within a 8% deviation from the previous input or similar stuff.

[rainyfree]

Please don't double post.

I would take that to mean before posting to the DB is the data correct on the page? In that case I would attempt to apply the Bussiness rules to test if all required data is present on the form, is all the data of the correct type? Then do the post to DB.

Sorry about that. I won't double post again.
"I would take that to mean before posting to the DB is the data correct on the page?" - calculate the mean of the whole data? can u tell me why?

"In that case I would attempt to apply the Bussiness rules to test if all required data is present on the form, is all the data of the correct type? "- sounds a good point. can u give me an example?

Many thanks.

[GaryMazzone]

No I mean I think that is what was being asked.

Say you have a field on the form for Last Name and it is a required field and is not allowed to be empty. I would check that there is data is the textbox and not just a space. Maybe the combination of LastName,FirstName,MiddleInitial and Suffix are required to be unique in the database I would attempt to test for uniqueness before attempting to insert the data.