Latihan 3 Statistik Ekonomi dan Bisnis

Venty IE 2009

Dosen: Pak Uka W. ; Bu Nanda N. Februari 2013

Steam and Leaf

• A survey of number of calls received by Southern Phone Company subscribers last week revealed the following information. Develop a steam and leaf chart? How many calls did subscriber receive?

52 43 30 38 30 42 12 46 39

37 34 46 32 18 41 5

• Two disadvantages to organizing the data into a frequency distribution:

(1) The exact identity of each value is lost

(2) Difficult to tell how the values within each class are distributed.

Stem Leaves

1 0 5

3 1 2 8

3 2

[7] 3 0024789

6 4 12366

1 5 2

Median, Quartile, and Percentiles

The Thomas Supply Company,Inc. is a distributor of small electrical motors. As with any business, the length of time customers take to pay their invoice is important. List below is the time in days, for sample of The Thomas Supply Company,Inc. Invoice. 13 13 13 41 45 41 41 50 51 47 47 54 47 53 62 27 26 20 34 34 31 34 36 37 38 35 56 82 67 35 a. Determine the first, second, and third quartiles b. Determine the 67th percentile

Urutkan data dari terkecil ke terbesar

13 13 13 20 26 27 31 34 34 34 35 35 36 37 41 41 41 45 47 47 47 50 51 53 54 56 62 67 82

Q1 = (30 +1) . 25/100 = 7.75

Value of Q1 = 31 +0.75 (34-31) = 33.25

Q2 = (30 +1) . 50/100 = 15.5 Q2= median

Value of Q2 = 38 +0.5 (41-38) = 39.5

Q3 = (30 + 1).75/100 = 23.25

Value of Q3 = 50 +0.25 (51-50) = 50.25

P67 = (30+1).67/100 = 20.77

Value of P67 = 47

Jika toko B ingin memberikan sangsi kepada 10% karyawan yang paling lama menyelesaikan 1 buah sepatu, bearpa menit waktu maksimal bagi pekerja agar dia tidak mendapatkan sangsi?

Toko A (menit) Toko B (menit)

Kelas Titik

Tengah

Jumlah

Karyawan

Kelas Titik

Tengah

Jumlah

Karyawan

30-34 32 3 30-34 32 1

35-39 37 5 35-39 37 2

40-44 42 12 40-44 42 13

45-49 47 10 45-49 47 17

50-54 52 15 50-54 52 14

55-59 57 8 55-59 57 6

60-64 62 2 60-64 62 2

Jumlah 55 Jumlah 55

Rerata hitung 47,55 Rerata hitung ??

Standar deviasi 7,5 Standar deviasi ??

Box Plot

A sample of 28 time share in Florida Revealed the following daily charges for a one bedroom suite. Construct a box plot to represent the data. Comment the distribution. (in $)

121 157 116 207 192 209 209

232 229 236 236 243 239 246

264 260 281 276 283 289 295

307 312 309 317 341 324 353

Membuat Box Plot

Step1: Create an appropriate scale along the horizontal axis.

Step 2: Draw a box that starts at Q1 and ends at Q3. Inside the box we place a vertical line to represent the median

Step 3: Extend horizontal lines from the box out to the minimum value and the maximum value

List the data :

116 121 157 192 207 209 209

229 232 236 236 239 243 246

260 264 276 281 283 289 295

307 309 312 317 324 341 353

Q1 = (28+1).25/100 = 7.25

Value of Q1 = 209 + 0.25 (229-209) = 214

Q2 = (28+1).50/100 = 14.5

Value of Q1 = 246 + 0.5(260-246) = 253

Q3 = (28 +1).75/100 = 21.75

Value of Q3 = 297 + 0.75(307-295) = 306

Outlier > Q1+1.5(Q3-Q1)

214 + 1.5(306-214) = 352

Outlier < Q1-1.5(Q3-Q1)

214 - 1.5(306-214) = 76

Min = 116, Max = 341

Skewness

Manakah dari data berikut ini yang dipengaruhi oleh keberadaan outliers?

a. Modus

b. Median

c. Persentil ke 75

d. Rerata hitung

Pemilik sebuah perusahaan baru-baru ini memutuskan untuk menaikkan gaji dari salah satu pegawainya, yang sudah mendapat gaji tertinggi, dengan 20%. Manakah dari pernyataan dibawah ini yang diharapkan terpengaruh oelh tindakannya?

a. Hanya rerata hitung

b. Hanya median

c. Hanya rerata hitung dan median

d. Rerata hitung, media, dan modus

Pada steam-and-leaf berikut ini, nilai-nilai bagian steam and leaf menunjukkan 10an dan 1an. Berapakah frekuensi dari kelas 35 – 45, yaitu {x; 35≤x<45}?

Steam Leaf

1 3 5 6 8 9

2 0 1 2 2 3 5 6 6 8 8 8 9

3 0 1 2 2 8

4 2 2