Hallo ....We are GLORY TWINKLE from Nedusi

IX E

We will present our project about STATISTICS

Let’s check it out !

STATISTICS

A. The Definition Of Statistic

• Statistics is a study or scientific method ofcollecting, organizing, processing, presenting, analizyng data and drawing a conclusion accordingto the result of the data analysis.

From the following definition, we know that statistics is closely releated to data.

• Data is the information obtained from theresult of observation or research .

• The singular form of data is datum

• Data can describe a situation, so that basedon the data we can draw a conclution

1) Presenting Data

According to the types, data can be divided into two. They are :

1. Qualitative dataare data releated to the category orcharacteristic of an object.For examples :a. Data about the cleanest country in the

world (Singapore, Japan, Australia, or theother)

b. Data about the best female singer(BoA, Taylor Swift, Beyonce, Rihanna, WhitneyHousten or the other)

Qualitative data are usually obtained by interview

2. Quantitative data, are obtained fromthe result of numerical recording (inthe form of numbers)

For examples are :

a. Data about the weight in the class(48kg, 45.5kg, 45kg, 49kg, 48kg,50kg and so on)

b. Data about the number of sister (2,3, 2, 4, 1, 0 and so on)

As we know, the data are used to draw aconclusion. But before draw a conclusion, thedata that have been collected beforehandarranged, processed, presented, then analyzedcarefully, accurately and according to the right

theory.

There are several examples of conclutions :a. The average of students in the class IX E is 14

years oldb. The favorite teacher in Nedusi is Mr. Yokoc. The favorite subject in class IX E is Mathematic

Based on the data that have been analyzed, wecan draw a conclusion

2). Collection of Data

• Collection of data is the beginning stage (thefirst step) in the statistical activity.

• Collecting data can be performed by interviewof questionnaire, then continued by one of thefollowing activities :

a. Counting

b. Measuring

c. Recording data by tallies

• Simple data is only consist of relatively smalldata.

• It isn’t necessary to group them, ordering datais enaugh

• In general, the collected statiscal data are stillscattered and the measurement isn’t in order.

• However, to simply presentation and processingof data, we need to order them from thelowest value to the highest value. After thedata are ordered, we can determine the highestand the lowest value of data.

3). Ordering Single Data

Measures Of Central Tendency

• The collected and even the ordered datadon’t automatically give clear information.

• To get clearer information, we needmeasures to represent the collection ofdata.

• The measures are known as the measuresof central tendency

• By knowing measures of centraltendency, we can find out the value of thecentralized data.

The Measures Of Central Tendency Consist Of 3

Measures, Namely :

1. MEAN (arithmetic mean) 2. MODE (the value that occurs most

often)3. MEDIAN (the middle value)

1. Mean• In statistic, the average value is usually called

arithmetic mean or simply mean.

• So, mean is the average value of all data values

• Mean is one of the measures of central tendency that is most often used.

• The mean of data set is the sum of all data values divided by the number of data.

☞Example : Data = 7 8 9 8 5 9 9 6 4

The ordered data =4 5 6 7 8 8 9 9 9

= 7.3

n

XX

2. Mode

• Mode is generally used to express the tendency which most frequently happens.

• In statistics, the mode means the value that occurs most frequently or the value of highest frequency.

Example :

Data = 3 5 8 6 5 9 8 8 6

The ordered data = 3 5 5 6 6 8 8 8 8 9

Based on the data above, the value of highest frequency is 8

No. Marks Tally Frequency

1. 3 l 1

2. 5 ll 2

3. 6 ll 2

4. 8 llll 4

5. 9 l 1

So, the mode is 8

3. Median• Median is a measure of central tendency used to analyze data.

• If the number of data ordered is odd, then the median is thedata value right in the middle that divides the data into twoequal parts

• And if the number of data ordered is even, then the median isthe mean of two data values in the middle

Median = The middle value after being ordered

Data : 9 9 7 5 8 7 3 6 4 The ordered data : 3 4 5 6 7 7 8 9 9

Median = 3 4 5 6 7 7 8 9 9

4 4Median

So, the median is 7

a. If n is odd, then the median is

b. If n is even, then the median is

Example :

Because n is odd (9), so the median is in the order to :

5

C. The Presentation Of Data

• The data collected and ordered according to the need should be presented in a certain form in such away that they can be read and interpreted easily

The presentation of statiscal data can be performed in two methods, they are :

1. Presented in the form of list or tablea. Frequency table of single datab. Frequency table of grouped data

2. Presented in the form of a diagram or grapha. Pictogram (A method of presenting information using picture)b. Bar chart (A method of presenting data in bars)c. Line graph (A method of presenting data in a line)d. Pie charts (A method of presenting data in a circular region)

A. Pictogram

B. Bar Chart

C. Line Graph

D. Pie Charts

Quartile

• Quartile means the grouping of four, split the data that has been sorted into four equal parts.

• To present quartile, we used Q symbol.

Q₁ = initial quartile / bottom quartile (¼)

Q₂ = middle quartile / median (¾)

Q₃ = upper quartile (²⁄₄)

We Have Some Observation In Class VII C And Class VII G

Curious ?Do you want to know ?

Serious ? Okay Let’s check it out !

Observation In Class VII G

Questions :1. How many sister

do you have?2. How many

brother do you have?

3. When you were in class six, what rank did you get ?

(Quantitative Data)

1. The Number of Sisters Owned by Students of VII G

0

2

4

6

8

10

12

Haven't

Sister

Have 1

Sister

Have 2

Sisters

Have 3

Sisters

Have 4

Sisters

Have 5

Sisters

Sisters

Haven't Sister

Have 1 Sister

Have 2 Sisters

Have 3 Sisters

Have 4 Sisters

Have 5 Sisters

Stu

dent

s

So, from the data we can make a conclution :

a. The students that haven’t sister are 10 students

b. The students that have 1 sister are 8 students

c. The students that have 2 sisters are 6 students

d. The students that have 3 sisters are 2 students

e. The student that have 4 sisters is nothing

f. The students that have 5 sisters are 2 students

The number of students that have the most sister are 2 studentsAnd the students that haven’t sister are 4 students

2. The Number of Brothers Owned by Students of VII G

10

9

3

6

Broters

Students That Haven't

BrotherStudents That Have 1

BrotherStudents That Have 2

BrothersStudents That Have 3

Brothers

So, from the data we can make the conclution :

a. The students that haven’t brother 10 students

b. The students that have 1 brother are 9 students

c. The students that have 2 brothers are 3 students

d. The students that have 3 brothers are 6 students

e. The student that have 4 brothers and 5 brothers is nothing

The number of students that have the most brothers (3 brothers) are 6 studentsAnd the number of students that haven’t brother are 10 students

3. The Rank Of Students VII G

When They Were In Class

Six

Ranked Students

1

2

3

4

5

8

9

10

11

12

13

14

18

19

20

4. The Interest or The Favorite Language in Grade VII C

0 2 4 6 8 10 12 14

Bahasa Indonesia

English

Japan

France

Bahasa Indramayu

Favorite Language

Bahasa Indonesia

English

Japan

France

Bahasa Indramayu

Observation In Class VII C

Question :

1. What kind of language do you like ?

2. Which country will be visited most ?

3. Which city will you go to your studytour ?

(Qualitative Data)

So, From The Data We Can Make Conclution :

a. The students who interested Bahasa Indonesia are 3students

b. The students who interested English are 14 students

c. The students who interested Japan Language are 9students

d. The students who interested France are 2 students

e. The student who interested Indramayu Language isnothing

So, English is the most interestedlanguage. And Indramayu language isn’tinterested with all students VII C

5. The Country Will Be Visited Most By Students VII C

41%

17%

24%

7% 4% 4% 3%

The Countries

South Korea

Japan

France

Saudi Arabia

Holand

Rumania

AustraliaThe number of students VII C is 28

students

So, from the data we can make the conclution :

o The number of students VII C will be visited South Korea are 12students

o The number of students VII C will be visited Japan are 5 students

o The number of students VII C will be visited France are 7 students

o The number of students VII C will be visited Saudi Arabia are 2students

o The number of students VII C will be visited Holand is 1 student

o The number of students VII C will be visited Rumania is 1 student

o The number of students VII C will be visited Australia is 1 student

So, the city will be visited most is South KoreaAnd the city will be visited least is Holand, Rumania, and Australia

6. The City That Very Want To Visit To Your Studytour

-2

0

2

4

6

8

10

12

0 2 4 6 8

Fre

quenc

y

Bali

Lombok

Yogyakarta

Paris

Jakarta

Bandung

Raja Ampat

So, from the data we can make the conclution

• The students who choose Bali to visit to their studytour are 11 students

• The students who choose Lombok to visit to their studytour are 5 students

• The students who choose Yogyakarta to visit to their studytour are 2 students

• The students who choose Paris to visit to their studytour are 5 students

• The student who choose Jakarta to visit to their studytour is nothing

• The student who choose Bandung to visit to their studytour is nothing

• The student who choose Raja Ampat to visit to their studytour is 1 student

So, the city that most choose to visit to students of VII C’s studytouris South KoreaAnd the cities that not choose to visit to students of VII C’s studytourare Jakarta and Bandung

We Have Learn About Statistics

So, please answer theseexercises

EXERCISE

1. Given the following data

2 6 8 1 4 3 5 3 9 4

6 8 4 2 5 5 2 5 5 5

4 8 7 7 6 9 4 6 7 5

Based on the data above :

a. Make the frequency table

b. Find the mean, the mode and the median

2. The mean mark ofmathematics test of 15students is 8.6 ifSofhie’s mark isincluded, then the meanmark becomes 8.7 findDinda’s mark in the test.

3. The mean weight of agroup of children is 38 kg.Children having a meanweight of 40 kg areadded, then the meanweight becomes 38.4 kg.Find the number ofchildren at first

4. Consider the table below

KINDS OF PEOPLE’S OCCUPATIONS IN VILLAGE A

NO. Kinds Of Occupations Frequency

1 Public Servants 56

2 Private Employees 42

3 Farmers 84

4 Traders 126

5 Workers 28

The frequency table above shows the data about the kinds of occupations of people at a village. Make a pie chart based on the data.

5. The number of classes and the classinterval in the table of frequencydistribution respectively are ...

Value Frequency

30-34 2

35-39 7

40-44 11

45-49 4

50-54 3

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