A web script calculating and updating the average of entered numbers

The title says it all. The home page will include a simple input box where people will enter a number, up to three digits. The user will submit the number, and we'll show a response text accordingly. (Like "too little" for 1-5, "moderate" for 6-10, "high" for 11-30, "too high" for 31+ We'll save each entry to a database, and calculate the average number (total number, divided by number of entries) and also show this to the user. We'll also say "you're above/below the average" That's pretty much it! I need this coded and implemented ASAP, hopefully today!