1. Star system changes

Hi. This is not exactly my homework. It's for a webpage that I manage. We have a rating system for movies, and we just changed from 4 stars to 10 star system. So I was wondering if you could help me write a formula to change all the stars.

So The problem is, the old system was
0 - 4 stars
And the new one is
1 - 10 stars
Here's how the numbers should be

0 = 1
0,5 = 2,123
1 = 3,25
1,5 = 4,375
2 = 5,5
2,5 = 6,625
3 = 7,75
3,5 = 8,875
4 = 10

So can this be translated into some kind of a formula, so that I can quickly see, when a movie avarage rating is 3,76, what that should be in the new system.

Cheers
Eysteinn

PS: If you are interested, this is for an Icelandic site called kvikmyndir.is that started in 1997

2. Originally Posted by Steinninn
Hi. This is not exactly my homework. It's for a webpage that I manage. We have a rating system for movies, and we just changed from 4 stars to 10 star system. So I was wondering if you could help me write a formula to change all the stars.

So The problem is, the old system was
0 - 4 stars
And the new one is
1 - 10 stars
Here's how the numbers should be

0 = 1
0,5 = 2,123
1 = 3,25
1,5 = 4,375
2 = 5,5
2,5 = 6,625
3 = 7,75
3,5 = 8,875
4 = 10

So can this be translated into some kind of a formula, so that I can quickly see, when a movie avarage rating is 3,76, what that should be in the new system.

Cheers
Eysteinn

PS: If you are interested, this is for an Icelandic site called kvikmyndir.is that started in 1997
You have a formula to get from the old system to the new system: (new) = (10/4) * (old). As long as you are just doing averages, just plug the old average into the formula as if it were a score: (new average) = (10/4) * (old average).

If you are doing something more complicated like a standard deviation, then you need to sub the formula into the standard deviation formula. I'd demonstrate, but LaTeX is down and it would be very messy to write out in ASCII.

-Dan