Statistik

Question

Carilah Persamaan regresi linier siderhana dari data dibawah ini
10 Perusahaan
Penjualan (Y) = 65, 62, 75, 70, 89, 94, 77, 90, 95, 68
Promosi (X) = 22, 20, 39, 24, 30, 32, 19, 29, 33, 25

rahmayetty · Answer

Dari data diperoleh
$\sum{X}=273$, $\sum{Y}=785$, 
$\sum{XY}=21861$, $\sum{X}^{2}=7821$, $\sum{Y}^{2}=63029$ $n=10$
Persamaan regresi 
$Y=a+bX$
$$\begin{aligned}b&=\frac{n\sum{XY}-\sum{X}\sum{Y}}{n(\sum{X}^{2})-(\sum{X})^{2}}\&=1\text{,}169\end{aligned}$$
$$\begin{aligned}a&=\frac{\sum{Y}(\sum{X^{2}}-\sum{X}(\sum{XY})}{n(\sum{X}^{2})-(\sum{X})^{2}}\&=46\text{,}572\end{aligned}$$
Maka persamaan regresi 
$$\begin{aligned}Y &= 46\text{,}572 + 1\text{,}169X\end{aligned}$$