Getting predictions right

[kontrol]

Hi, I am not a statistician so please forgive me if my question is not in order.
I have been trying to work on some few prediction based on past records.
from samples of 100 and above that i have been working which happens to all the data i have but on the increase, I predict about 16 prices ranges and all the time i get about three out of the sixteen failing.
how do i work around it. is there something i am doing wrong?

 

[Miner]

You need to provide more information. Are you trying to perform a time series analysis to predict the future based on past performance, or are you trying to use a regression model to predict based on other variables?

 

[kontrol]

i am trying to predict based on past performance.

 

[Miner]

Can you attach your data? Designate which were used for the analysis, the predicted values and the actual results. Time series analysis is pretty complex, and it would be nearly impossible to diagnose without the data.