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Regresi linier sederhana. Kuliah #2 analisis regresi Usman Bustaman. Apa itu ?. Regresi Linier Sederhana. Regresi ( Buku 5: Kutner , Et All P. 5). Sir Francis Galton (latter part of the 19th century): studied the relation between heights of parents and children
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Regresi linier sederhana Kuliah #2 analisisregresi UsmanBustaman
Apaitu? • Regresi • Linier • Sederhana
Regresi(Buku 5: Kutner, Et All P. 5) • Sir Francis Galton (latter part of the 19th century): • studied the relation between heights of parents and children • noted that the heights of children of both tall and short parents appeared to "revert" or "regress" to the mean of the group. • developed a mathematical description of this regression tendency, • today's regression models (to describe statistical relations between variables).
m B linier • Masihingat Y=mX+B? • Slope? • Konstanta? Y X
Linier lebihlanjut… • Linier dalamparamater… • Persamaan Linier orde 1: • Persamaan Linier orde 2: • Dst… (orde pangkattertinggi yang terdapatpadavariabelbebasnya)
m B sederhana • Relasiantar 2 variabel: • 1 variabelbebas (independent variable) • 1 variabeltakbebas (dependent variable) • Y=mX+B? • Manavariabelbebas? • Manavariabeltakbebas? Y X
Bagaimanamembangun Model Regresi Linier Sederhana?Analisis/Comment Grafik-2 Berikut:
Fungsi rata-2 (Mean Function) If you know something about X, this knowledge helps you predict something about Y.
Prediksiterbaik… • Bagaimanamengestimasi parameter dengancaraterbaik…
Regresi Linier Populasi Koefisienregresi Sampel ˆ Y = b0 + b1Xi
e = b b + Y X i 0 1 Regresi Linier Model Y ? (the actual value of Yi) Yi Xi X
Regresiterbaik = minimisasi error • Semua residual harusnol • Minimum Jumlah residual • Minimum jumlahabsolut residual • Minimum versiTshebysheff • Minimum jumlahkuadrat residual OLS
Assumptions • Linear regression assumes that… • 1. The relationship between X and Y is linear • 2. Y is distributed normally at each value of X • 3. The variance of Y at every value of X is the same (homogeneity of variances) • 4. The observations are independent
Asumsilebihlanjut…Alexander Von Eye & ChristofSchuster (1998) Regression Analysis for Social Sciences
Asumsilebihlanjut…Alexander Von Eye & ChristofSchuster (1998) Regression Analysis for Social Sciences
Maknakoefisienregresi • b0 ≈ ….. • b1≈ ….. x = 0 ? - Tinggivsberatbadan - Nilai math vs stat - Lama sekolahvspendptn - Lama training vsjmlproduksi …….
A2 B2 C2 yi C y A B SSE Variance around the regression line Additional variability not explained by x—what least squares method aims to minimize SSR Distance from regression line to naïve mean of y Variability due to x (regression) SST Total squared distance of observations from naïve mean of y Total variation B A C yi x Regression Picture
SST (Sum Square TOTAL) Variance to be explained by predictors (SST) Y
SSE & SSR X Variance explained by X (SSR) Y Variance NOT explained by X (SSE)
SST = SSR + SSE Variance to be explained by predictors (SST) X Variance explained by X (SSR) Y Variance NOT explained by X (SSE)
KoefisienDeterminasi Coefficient of Determination to judge the adequacy of the regression model Maknanya: …. ?
Salah pahamttg r2 • R2tinggi prediksisemakinbaik …. • R2 tinggi model regresicocokdgndatanya … • R2rendah (mendekatinol) tidakadahubunganantaravariabel X dan Y …
Korelasi Buktikan…! Pearson Correlation…? Correlation measures the strength of the linear association between two variables.
Assumptions • Linear regression assumes that… • 1. The relationship between X and Y is linear • 2. Y is distributed normally at each value of X • 3. The variance of Y at every value of X is the same (homogeneity of variances) • 4. The observations are independent
Uji parameter RLS • Linear regression assumes that… • 1. The relationship between X and Y is linear • 2. Y is distributed normally at each value of X • 3. The variance of Y at every value of X is the same (homogeneity of variances) • 4. The observations are independent
SelangKepercayaankoefisienregresi Confidence Interval for b1
SelangKepercayaankoefisienregresi Confidence Interval for the intercept