# Finding the Confidence Interval for Beta

Given this set of data:

(x,y): (-9,10.5), (-7,18.5), (-5,22.6), (-3,27.2), (-1,31.2), (1,33), (3,44.9), (5, 49.4), (7,35), (9,27.6)

Find a 90% confidence interval for beta 2(B2) [note: this deals with the model y=B0+B1X+B2X^2+e, e is the error, e~N(0, o~^2) (where o~ is sigma, the variance)] Is there evidence of a quadratic effect in the relationship between x and y? Use a 10% level test if B2=0.

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#### Solution Preview

Here are the fundamental how to solve this problem:<br>

<br>1) Looking at the equation

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<br>y=B0+B1X+B2X^2+e,

<br>It is evident that there is a quadratic relationship between the two variables - why? Because B2 is to the power of 2. In a linear model, all of ...

#### Solution Summary

This solution will teach you step by step how to fins a confidence interval given a set of data.