This document discusses statistics concepts including measures of central tendency (mean, median, mode), data collection and presentation methods (tables, charts, graphs), measures of spread (range, interquartile range, variance, standard deviation), and box and whisker plots. It provides examples of when to use the mean vs median vs mode based on the goal. It also discusses calculating quartiles, interquartile range, and representing data using a box and whisker plot.

1. STATISTICS
XI Social Semester I
by
Anastasia Putriandi SMAK1 JKT

2. STATISTICS IN REAL LIFE
• Pemilihan ketua ketua kelas
• PEMILU
• Riset/Penelitian
• Apa lagi?

3. Kompas, Selasa 6 Juli 2010

4. STATISTICS

5. Pengumpulan dan Penyajian Data

6. Proses pengumpulan data
Populasi
Sampel
x,s
µ, σ
Digunakan untuk menaksir

7. PENYAJIAN DATA

8. Table of Frequency
Kompas, 3 Juni 2010, page 19

10. Barchart
Kompas, 3 Juni 2010 page 18

12. Line Chart

13. STATISTICS

14. UKURAN PEMUSATAN/
MEASURES OF CENTRAL TENDENCY
( common averages: mean, median, mode)
mean: regular meaning of "average“
median: middle value
mode: most often

15. For a probability distribution, the mean is also called the
expected value of the random variable. For a data sample, the mean is
also called the average

16. Student: Which one is better: mean,
median or mode?
• Mentor: It depends on your goals. I can
give you some examples to show you
why. Consider a company that has nine
employees with salaries of 35,000 a year,
and their supervisor makes 150,000 a
year. If you want to describe the typical
salary in the company, which statistics will
you use?
• Student: I will use mode (35,000),
because it tells what salary most people
get.

17. • Mentor: What if you are a recruiting officer for
the company that wants to make a good
impression on a prospective employee?
• Student: The mean is (35,000*9 + 150,000)/10 =
46,500 I would probably say: "The average
salary in our company is 46,500" using mean.
• Mentor: In each case, you have to decide for
yourself which statistics to use.
• Student: It also helps to know which ones other
people are using!

18. i x[i] Quartile
1 102
2 104
3 105 Q1
4 107
5 108
6 109 Q2(Median)
7 110
8 112
9 115 Q3
10 116
11 118

19. Bagaimana jika banyaknya data
genap?

20. Upper and lower quartiles
Data 6, 47, 49, 15, 43, 41, 7, 39, 43, 41, 36
Ordered data 6, 7, 15, 36, 39, 41, 41, 43, 43, 47, 49
Median 41 Range : 49-6 (Jangkauan)
Upper quartile 43 Interquartile range : 43-15 [Q3-Q1]
15 Semi-quartile : (43-15)/2 [ ½ (Q3-Q1)]
Lower quartile

21. UKURAN PENYEBARAN
Measures of Spread

22. Box and whisker plots

23. • The oldest person in Mathsminster is 90.
The youngest person is 15.
• The median age of the residents is 44, the
lower quartile is 25, and the upper quartile
is 67.
• Represent this information with a box-and-
whisker plot.

24. Ukuran pemusatan yang lain:
1. Simpangan rata-rata
• Simpangan rata-rata
n
∑ xi − x
SR = i =1
n

25. 2. Ragam (Variance)
(x )
n
∑
2
i −x
s =
2 i =1
n

26. 3. Simpangan Baku
(Standard Deviation)
s= s 2