Sample and Population

By:

Group 5

1. Altafiyani Rahmatika

2. Gina Nuryustika Rizal

3. Jody Furqon Sanjaya

4. Wini Safitri

Class IX D

START!

Select!1.

DEFINITION 2. SAMPLE AND POPULATION

IN DAILY LIFE

3.THE SAMPLING PROCESS

5. EXERCISE

4. EXAMPLE

Definition

What is the meaning of population?

Population is all objects being studied.

And, what is the meaning of sample?

Sample is a part of population being studied

or observed.

Sample and Population in Daily LifeSuppose we want to know the average weight of Junior High

School students in Subang. Considering limited time, labor and cost, we cannot measure all the students. Thus, we should pick a random sample consisting of all students from a number of public or private schools.

In this case :

i. all Junior High School students in Subang constitute the population,

ii. Students whose heights are measured constitute the sample.

The Sampling Process

• Define population (N) to be

sampled

• Determine sample (n) from

population (N) to be

observed

• Determine an inference of

population based on sample

POPULATION (N)

SAMPLE (n)

INFERENCE

Example 1SMP B has 8 classes of students from each grade VII,

VIII, IX. Suppose that the principal wants to conduct a research on the relation between parental socioeconomic status and a student’s outcome, determine:

a. the population

b. the sample

Answer:

a. The population is all the students in SMP B.

b. The sample is some students from each grade VII, VIII, and IX selected randomly.

Example 2

A research has been carried out to determine the pollution level in a lake.

a. What is the population?

b. How to collect the sample?

Answer:

a. The population is a lake.

b. A research only observe some quantities of water taken randomly as the sample of the lake (population) to determine the pollution level in a lake.

Exercise

1. The department of National Education is conducting a research on the result of the national final exam in a province.

Determine.

a. the population

b. the sample

Answer:

a. The population is the result of the national final exam in a national (all province)

b. The sample is the result of the national final exam in a province.

2. A farmer cultivate his ½ ha rice field. Being properlycultivated, the rice field yields good quality crop. Inharvest time, he gets 8 kg of unhusked rice fieldtotaling 10 m2 in area.

a. What is the population?

b. What is the sample?

c. Based on the sample, estimate the total mass of unhusked rice grains the farmer can harvest

Answer :

a. The population is ½ ha rice field.

b. The sample is 8 kg of unhusked rice grains from different parts of his rice field totalling 10 m2 of rice field.

c. The population = ½ ha rice field

= ½ hm2

= ½ x 10000

= 5000 m2

The sample = 8 kg of 10 m2 in area of ½ ha rice field

= 8 kg/10 m2

The total mass of unhusked rice grains =

Sample x Population

4000 kg

Thus, the total mass of unhusked rice grains the farmer can harvest is 4000 kg.

= x 5000 m2

=

2