# Thread: Problem desired least square lines

1. ## Problem desired least square lines

The failure rate of a certain electronic device is suspected to increase linearly with its temparature . Fit a least- square linear line through the data (two measurments were taken for each given temparature)

$
\begin{array}{|c|c|c|c|c|c|c|}
Temp^{\cdot} F & 55 & 65 & 70 & 85 & 95 & 105 \\
Failure \; rate. 10^6 & 1.90 & 1.93 & 1.97 & 2.00 & 2.01 & 2.01 \\
&1.94 & 1.95 & 1.97 & 2.02 & 2.02 & 2.04
\end{array}
$

i) Obtain desired least-square line
ii) Obtain predicted failure rate at $70^{\cdot}$ F

2. Originally Posted by Stats
The failure rate of a certain electronic device is suspected to increase linearly with its temparature . Fit a least- square linear line through the data (two measurments were taken for each given temparature)

$
\begin{array}{|c|c|c|c|c|c|c|}
Temp^{\cdot} F & 55 & 65 & 70 & 85 & 95 & 105 \\
Failure \; rate. 10^6 & 1.90 & 1.93 & 1.97 & 2.00 & 2.01 & 2.01 \\
&1.94 & 1.95 & 1.97 & 2.02 & 2.02 & 2.04
\end{array}
$

i) Obtain desired least-square line
ii) Obtain predicted failure rate at $70^{\cdot}$ F
Can you use technology or must it be done by hand? If by hand, please post the all formulae you have been given for doing this.

3. I have to guess that your model is $y=\beta_0+\beta_1x+\epsilon$.
I have JMP here.
It's real easy using that.