4 - 1 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved.

4 - 2 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Review •Statistika dalam bisnis •Tipe Data •Tabulating and presenting data •Central tendency •Varians •Homogen/heterogen •Hubungan antara 2 variabel

4 - 3 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Weighted Mean Weighted mean adalah data: x 1, x 2,... x n, dan mempunyai bobot w 1, w 2,...,w n, rumusnya adalah:

4 - 4 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. 89.0$  50.44$  )50.0($  )10.1($15  )90.0($15  )75.0($15   w μ Selama hari sabtu penjual minuman menjual sebanyak 50 minuman dengan deskripsi sbb: …5 minuman seharga $0.50 …15 minuman seharga $0.75 …15 minuman seharga $0.90 …15 minuman seharga $1.10 Hitung: - weighted mean dari harga minuman yang terjual-

4 - 5 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Sampel dari 10 bioskop dihitung jumlah film yang ditayangkan minggu lalu. Carilah Mean dari distribusi frekwensi yang telah dibuat. Mean dari Distribusi Frekwensi

4 - 6 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Lanjutan 6610Total Krg dr Krg dr Krg dr Krg dr Krg dr 3 (f)(M) Class Midpoint (M) Frequency f Movies Showing Mean dari Distribusi Frekwensi n fM  

4 - 7 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. =  Lanjutan (f)(M) Class Midpoint Frequency f Movies Showing 6610Total Mean dari Distribusi Frekwensi n fM   Formula n fM  

4 - 8 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Median dari Distribusi Frekwensi Median dari Distribusi Frekwensi •M = Median •L = batas bawah kelas median •n = jumlah sampel •CF = frekwensi di bawah kelas median •f = frekwensi kelas median

4 - 9 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Menentukan posisi kuartil •Lp = Posisi kuartil •n = jumlah sampel •P = persentasi kuartil

Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Simpangan Baku dari Distribusi Frekwensi Rumus untuk mencari Simpangan Baku dari distribusi frekwensi: f = frekwensi kelas and M is class midpoint dimana

Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Koefisien dari Skewness antara up to Skewness  σ Mean  Median SK = 3 Bila koefisien skewness = 0, berarti simetrik Rumusnya adalah: Kemiringan/Kemencengan

Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Sk = (Bowley) (Q - Q ) (Q - Q ) – (Q - Q ) Menghitung Koefisien Bowley: Catatan: Menurut Bowley, apabila > +30% atau < -30%, menunjukkan bahwa distribusi frekwensi memiliki tingkat kemencengan yang tinggi.