Statistics (statistika)

-statistics is the science of collecting, analyzing, interpreting or explaining, and presenting data

it can be employed to make an accurate decision

A. collecting data

1.definition of data and datum
a.datum: facts needed
b.data: collection of several datum

2.definition of population and sample
a.population: all subjects being studied 
b.sample: part of population being studied

3.type of data
a. discrete data (data cacahan)
 data obtained by counting (menghitung)
 example: data jumlah siswa kelas 9
          data jumlah papan tulis di SDH
b. continu data (data ukuran)
 data obtained by measuring (mengukur)
 example: data tinggi badan siswa
          data ukuran sepatu
-qualitative data: data not in form of number
 example: data makanan kesukaan kelas 9
          data warna tinja setiap hari

4.methods in data collecting

a.interview (wawancara)
b.questionnaire (pertanyaan tertulis)
c.observation (pengamatan)

5.measures of central tendency (ukuran pemusatan data)
a.mean (rata-rata)
b.median (nilai tengah)
c.modus (paling sering muncul)

6.measures of dispersion (ukuran penyebaran data)
a.range (jangkauan)
b.quartile (Q1, Q2, Q3)
c.interqualtile range

B.presenting statistical data

1.pictogram (pictorial graph)
2.bar chart
3.line chart
4.pie chart

measures of central tendency (ukuran pemusatan data)

a) mean (rata-rata)



b) median (nilai tengah)
-data berjumlah ganjil


-data berjumlah genap


c) modus
-data dengan frekuensi (muncul) paling banyak

measures of dispersion (ukuran penyebaran data)

a.range (jangkauan)
  R= biggest datum - smallest datum

b. quartile

data ganjil



data genap



c. Interquartile Range


d. simpangan kuartil


contoh soal:

1. tentukan Q1,Q2,Q3 dari: 3,4,7,8,7,4,8,9,10,8,3,7,12,4,7,8,8,9

jawab:


Rata-rata Gabungan (RRG)

contoh:


Statistic diagrams