TUGAS KE-3

Contoh Soal Regresi
CONTOH SOAL :
Diketahui suatu penelitian terhadap hubungan antara nilai biaya periklanan dengan tingkat penjualan dari
sebuah koperasi adalah sebagai berikut : (dalam ribuan rupiah)

Biaya periklanan Tingkat Penjualan
50 40
51 46
52 44
53 55
54 49

a.Tentukan persamaan regresinya
b.Berapa besarnya koefisien korelasi dan koefisien determinasinya ?
c. Berapa besarnya kesalahan standar estimasinya ?
d. Dengan tingkat signifikasi 10%, ujilah hipotesis yang menyatakan bahwa hubungan antara
biaya periklanan dan tingkat penjualan sedikitnya 40%!


Jawab :
a.Menentukan persamaan regresinya
Langkah 1 :
Menentukan variable X dan variable Y. Dalam soal ini variable biaya periklanan merupakan variable X dan tingkat penjualan merupakan variable Y.
Langkah 2 :
Membuat table regresi sederhana
Periklanan (X) Tkt. Penjualan (Y) (X)2
50 40 2500
51 46 2601
52 44 2704
53 55 2809
54 49 2916
260 234 13530


Langkah 3 :
Menentukan koefisien a dan koefisien b
b = n ∑XY – ∑X.∑Y
n ∑X2 – (∑X2)
= 5 (12195) –(260)(234) 5 (13530) – (260)2
= 2,7
a = ∑Y – b ∑X

n= {(234) – 2,7 (260)} / 5
= -93,6

Langkah 4:
Menentukan persamaan regresi linier sederhana
Y = a + b (X)
Maka persamaan regresi dalam soal ini adalah :
Y = -93,6 + 2,7 (X)

b. Menentukan besarnya koefisien korelasi dan koefisien determinasi
Koefisien korelasi :

r = n (∑XY) – (∑X) (∑Y)
[ n (∑X2) – (∑X2)]1/2 [ n (∑Y2) – (∑Y)2]1/2
= 5(12195) – (260) (234)
[ 5 (13530) – (260)2] 1/2 [ 5 (11078) – (234)2]1/2
= 0,76


C. Menentukan besarnya kesalahan standar estimasi
Se = √∑Y2 – a ∑Y ¬¬– b ∑XY)n-2
= √( 11078 - (-93,6) (234) – (2,7) (1915))5 -2
= 4,24

d. Pengujian Hipotesis
1. Tentukan Ho dan Ha
Ho : β ≥ 0,4
Ha : β <>
2.Uji hipoteis 1 arah
3. Tingkat signifikan
alpha = 0,1


4.Wilayah kritis t ()
db = n – 2
= 5-2
= 3
t (0,1 ; 3) = 1,638
5.Nilai hitung
Sb = Se / √ ((∑X2) – ((∑X)2 / n)
= 4,24 / √(13530 – (260)2 / 5) = 1,342
t hitung = b – β / Sb
= 2,7 - 0,4 / 1,342 = 1,714


6. Keputusan : terima Ho, tolak Ha
7. Kesimpulan :

Pendapat yang menyatakan bahwa hubungan biaya periklanan dengan tingkat penjualan lebih kecil (<) dari 0,4 adalah benar, dimana biaya mempengaruhi tingkat penjualan sebesar 57.76%

Conditional Sentences / If-Clauses

Conditional Sentences are also known as Conditional Clauses or If Clauses. They are used to express that the action in the main clause (without if) can only take place if a certain condition (in the clause with if) is fulfilled. There are three types of Conditional Sentences.
Conditional Sentence Type 1
→ It is possible and also very likely that the condition will be fulfilled.
Form: if + Simple Present, will-Future
Example: If I find her address, I’ll send her an invitation.

Conditional Sentence Type 2
→ It is possible but very unlikely, that the condition will be fulfilled.
Form: if + Simple Past, Conditional I (= would + Infinitive)
Example: If I found her address, I would send her an invitation.

Conditional Sentence Type 3
→ It is impossible that the condition will be fulfilled because it refers to the past.
Form: if + Past Perfect, Conditional II (= would + have + Past Participle)
Example: If I had found her address, I would have sent her an invitation.

è NOUN

A noun is a word used to name a person, animal, place, thing, and abstract idea.
Countable Nouns
A countable noun is a noun with both a singular and a plural form, and it names anything (or anyone) that you can count.
We painted the table red and the chairs blue.
Miriam found six silver dollars in the toe of a sock.
UnCountable Nouns
A non-countable noun is a noun which does not have a plural form, and which refers to something that you could (or would) not usually count.
Joseph Priestly discovered oxygen.
Collective Nouns
A collective noun is a noun naming a group of things, animals, or persons. You could count the individual members of the group, but you usually think of the group as a whole is generally as one unit.
The flock of geese spends most of its time in the pasture.
The jury is dining on take-out chicken tonight.

Noun Plurals
Most nouns change their form to indicate number by adding "-s" or "-es", as illustrated in the following pairs of sentences:
When Matthew was small he rarely told the truth if he thought he was going to be punished.
Many people do not believe that truths are self-evident.

è Modals

Modal verbs are special verbs which behave very differently from normal verbs. Here are some important differences:
1. Modal verbs do not take "-s" in the third person.
Examples:
• He can speak Chinese.
• She should be here by 9:00.
2. You use "not" to make modal verbs negative, even in Simple Present and Simple Past.
Examples:
• He should not be late.
• They might not come to the party.
3. Many modal verbs cannot be used in the past tenses or the future tenses.
She musted study very hard


Common Modal Verbs
Can
Could
May
Might
Must Ought to
Shall
Should
Will
Would



è VERB

A verb is a kind of word (see part of speech) that usually tells about an action or a state and is the main part of a sentence
Verbs are also classified as either finite or non-finite.
A finite verb makes an assertion or expresses a state of being and can stand by itself as the main verb of a sentence.
• The truck demolished the restaurant.
• The leaves were yellow and sickly.
Non-finite verbs (think "unfinished") cannot, by themselves, be main verbs:
• The broken window . . .
• The wheezing gentleman . . .

• IRREGULAR VERBS
Irregular verbs change completely in the past tense. Unlike regular verbs, the past tense forms of irregular verbs are not formed by adding ed.

Examples:
Present: know
Past: knew
Past Participle: known

• REGULAR VERBS
Verbs have three principle parts. They are present, past, and past participle. For regular verbs, the past tense is formed by adding ed to the present tense; and the past participle is formed by using the past tense verb with a helping verb such as has, have, or had.

Examples:
Present: invite
Past: invited
Past Participle:invited



è ARTICLE

An article is a word that combines with a noun to indicate the type of reference being made by the noun. Articles specify the grammatical definiteness of the noun, in some languages extending to volume or numerical scope. The articles in the English language are the, a, and an.
Articles are usually characterized as either definite or indefinite.

Definite article
A definite article indicates that its noun is a particular one identifiable to the listener. It may be the same thing that the speaker has already mentioned, or it may be something uniquely specified. The definite article in English is the.
Ex :The children knew the fastest way home.

Indefinite article
An indefinite article indicates that its noun is not yet a particular one identifiable to the listener. It may be something that the speaker is mentioning for the first time, or its precise identity may be irrelevant or hypothetical, or the speaker may be making a general statement about any such thing. English uses a or an (depending on the initial sound of the next word) as its indefinite article.
Ex : She had a house so large that an elephant would get lost without a map.



è ADVERB

Kinds of Adverbs
Adverbs of Manner
She moved slowly and spoke quietly.

Adverbs of Place
She has lived on the island all her life.
She still lives there now.

Adverbs of Frequency
She takes the boat to the mainland every day.
She often goes by herself.

Adverbs of Time
She tries to get back before dark.
It's starting to get dark now.
She finished her tea first.
She left early.

Adverbs of Purpose
She drives her boat slowly to avoid hitting the rocks.
She shops in several stores to get the best buys.