Finding Acceleration Using a Table: Small Graphing Question | Homework Help

[BayernBlues]

Homework Statement

I have a question for a graph where I'm basically trying to find the acceleration using a table which has a time squared value starting at 7.132 seconds squared and ending at 9.686 seconds squared. I need to find a regression (I need to find the slope for the line of best fit. This is the graph:

The first problem is the error bars. I got y error bars but when I click on format options for the excel graph, it doesn't show x bars options so how do I add error bars? And my other question is, how/should I add (0,0) to the graph because obviously the displacement is 0 m at 0 seconds but this wasn't conducted in the experiment so wouldn't it skew the slope of the line of best fit?

Homework Equations

Here's the relation:
y= mx + b --------> s(displacement) = 1/2 a(acceleration)*t^2(seconds squared)

and here's the table:

-(s)--------(t^2)
113.76-----7.132
123.56-----7.896
133.3------8.588
143.66-----9.321
152.9------9.686

The Attempt at a Solution

http://img106.imageshack.us/img106/2456/nettles1qb0.png

 

[BayernBlues]

Should I set 7.132 to be the x intercept?