Data Analysis 1. Validity

CHAPTER IV RESERACH RESULT

C. Data Analysis 1. Validity

From the histogram above, it is stated M = 55,35 and SD = 14,33. To determine the category student‟s score was good, medium, or low, the researcher grouped scores using the standart as follows:

1. More than M + 1.SD (55,35 + 14,33 = 67) is categorized into good 2. Between M – 1.SD to M + 1.SD (41 – 67) is categorized into

medium

3. Less than M – 1.SD (55,35 – 14,33 = 41) is categorized into low It can be seen that the scores which are more than 67 is considered good, while the scores which are less than 41 is low

C. Data Analysis

11 0,338 0,30 Valid

12 0,380 0,30 Valid

13 0,279 0,30 Invalid

14 0,158 0,30 Invalid

15 0,160 0,30 Invalid

16 0,300 0,30 Valid

17 0,063 0,30 Invalid

18 0,201 0,30 Invalid

19 0,350 0,30 Valid

20 0,136 0,30 Invalid

21 0,227 0,30 Invalid

22 0,228 0,30 Invalid

23 0,208 0,30 Invalid

24 0,367 0,30 Valid

25 0,350 0,30 Valid

26 0,174 0,30 Invalid

27 0,264 0,30 Invalid

28 0,288 0,30 Invalid

29 0,308 0,30 Valid

30 0,337 0,30 Valid

31 0,294 0,30 Invalid

32 0,211 0,30 Invalid

33 0,429 0,30 Valid

34 0,300 0,30 Valid

35 0,306 0,30 Valid

36 0,125 0,30 Invalid

37 0,266 0,30 Invalid

38 0,346 0,30 Valid

39 0,170 0,30 Invalid

40 0,300 0,30 Valid

41 0,219 0,30 Invalid

42 0,148 0,30 Invalid

43 0,328 0,30 Valid

44 0,295 0,30 Invalid

45 0,399 0,30 Valid

46 0,372 0,30 Valid

47 0,251 0,30 Invalid

48 0,421 0,30 Valid

49 0,390 0,30 Valid

50 0,257 0,30 Invalid

From the table above, we can find 28 invalid numbers they are number

3,4,5,6,8,10,13,14,15,17,18,20,22,23,26,27,28,31,32,36,37,39,41,47,50.

And we find 22 valid numbers, they are number

1,2,7,9,11,12,16,19,24,25,29,30,33,34,35,38,40,43,45,46,48,49.

2. Reliabilty

In this research used Spearman Brown (Split half) formula to measure the reliability of the test. The formula is ⁴⁸ :

ri = 2�

1 + �

r_i = the internal reliability of all the instrument

rb = the correlation of product moment between the first half and the second half

ri = ^2�

1+ �

ri =^{2 � 0,76606}

1+0,76606 ri = ^1,532121

1,76606 = 0,867536

If rcount > rtable, the instrument is reliable If r_count > r_table, the instrument is not reliable

Table 4.3

Recapitulation of Test Item Reliability

’r’ arithmetic ’r’ table Explanation

0,867536 0,433 Reliable

From the interpretation above, this research has 21 of number. So, df

= ( 21- 2) = 19. So,”r” table of 5% is 0,433, ”r” count is 0,867536. It

48 Sugiyono, Metode Penelitian Kuantitatif, Kualitatif dan R&D,(Bandung:Alfabeta,2006),131.

can be concluded that ”r” count > ”r”table (0,867536> 0,433), so the instrument is reliable.

3. Item Difficulty

The difficulty of an item can be described statistically as the proportion of students who can answer the item correctly. The higher the value of difficulty, the easier the item.

Table 4.4

Calssification of Item Difficulty The amount of P Interpretation

Less than 0,30 To difficult

0,30-0,70 Medium

More than 0,70 Too easy

The result of analysis classified item difficulty in three groups :

1. P> 0.7 (easy) = if prop. Correct higher than 0.7 this item classified as easy item.

2. 0.3 ≤ p ≤ 0.70 (medium) = if prop. Correct hihger than or as same as 0.3 and lower than or as same as 0.7 this item classified as moderate item.

3. P < 0.3 (difficult) = if prop. Correct lower than 0.3 this item classified as difficult item

Table 4.5

Analysis prop. Correct/difficulty

Item number

Item difficulty (P) P =

� �

�

Interpretation

1 P = ⁵²

72 = 0,72

Too easy 2 P = ⁵⁴

72 = 0,75 Too easy

3 P = ⁴⁶

72 = 0,63 Medium

4 P = ⁴⁴

72 = 0,61 Medium

5 P = ⁵⁵

72 = 0,76 Too easy

6 P = ⁴⁹

72 = 0,68 Medium

7 P = ⁵⁵

72 = 0,76 Too easy

8 P = ⁴⁷

72 = 0,65 Medium

9 P = ³⁸

72 = 0,52 Medium

10 P = ⁴⁶

72 = 0,63 Medium

11 P = ⁵¹

72 = 0,70 Too easy

12 P = ³⁹

72 = 0,54 Medium

13 P = ⁴⁴

72 = 0,61 Medium

14 P = ⁵²

72 = 0,72 Too easy

15 P = ⁴⁴

72 = 0,61 Medium

16 P = ⁵³

72 = 0,73 Too easy

17 P = ⁵⁸

72 = 0,80 Too easy

18 P = ⁴⁸

72 = 0,66 Medium

19 P = ⁴⁵

72 = 0,62 Medium

20 P = ⁴⁰

72 = 0,55 Medium

21 P = ⁴³

72 = 0,59 Medium

22 P = ⁴⁸

72 = 0,66 Medium

23 P = ⁴¹

72 = 0,56 Medium

24 P = ⁵¹

72 = 0,70 Too easy

25 P = ⁵²

72 = 0,72 Too easy

26 P = ⁴³

72 = 0,59 Medium

27 P = ⁵²

72 = 0,72 Too easy

28 P = ⁵²

72 = 0,72 Too easy

29 P = ³⁶

72 = 0,5 Medium

30 P = ⁴⁷

72 = 0,65 Medium

31 P = ³⁹

72 = 0,54 Medium

32 P = ³⁹

72 = 0,54 Medium

33 P = ⁵¹

72 = 0,70 Too easy

34 P = ³⁸

72 = 0,52 Medium

35 P = ⁴⁷

72 = 0,65 Medium

36 P = ³⁵

72 = 0,48 Medium

37 P = ⁵⁷

72 = 0,79 Too easy

38 P = ⁵⁰

72 = 0,69 Medium

39 P = ⁴⁷

72 = 0,65 Medium

40 P = ³⁵

72 = 0,48 Medium

41 P = ⁴⁹

72 = 0,68 Medium

42 P = ⁵⁵

72 = 0,76 Too easy

43 P = ⁴⁴

72 = 0,61 Medium

44 P = ⁴¹

72 = 0,56 Medium

45 P = ⁴⁵

72 = 0,62 Medium

46 P = ⁵⁴

72 = 0,75 Too easy

47 P = ⁴⁶

72 = 0,63 Medium

48 P = ⁴⁵

72 = 0,62 Medium

49 P = ⁴⁵

72 = 0,62 Medium

50 P = ⁵⁶

72 = 0,77 Too easy

From the table above, there are three classification in item difficulty level. They are as follows :

Table 4.6

Classification of Item Difficulty

Classification No. Items Percent (%)

Too easy 1,2,5,7,11,14,16,17,24,25,27,28,33, 37,42,46,50

34 % Medium 2,4,6,8,9,10,12,13,15,18,19,20,21,

22,23,26,29,30,31,32,34,35,36,38, 39,40,41,43,44,45,47,48,49

66 %

Too diificult - 0 %

Based on that classification above, the easy item showed 34% too easy item, 66% medium item, and 0% difficult item.From table 4.6 this consist many too easy item. In addition from table 4.6 showed item 7 has prop correct 0,76 it means is too easy.

From table 4.7 showed column number of the student, the column give information how many students can answer correctly that item. From table showed there are 52 students can answer correctly from item no. 1 from 72 students, it means 20 students who answer incorrectly. So, this item classified as easy item. From item no 2. There are 54 students who answer correctly and this item classsified has medium item. And for items classified difficulty item is empty.

4. Item Discrimination

A good item should be able to discriminate students with high scores from those low scores. To score item discrimintion can be classified as below:

Table 4.7

Classification of Item Discrimination The amount of

indeks diskriminasi item (D)

Classified : Interpretation : Less than 0,20 Bad An items in question

once the

distinguishing weak is not considered a good distinguishing features

0,20 – 0,40 Fairly bad An items term in question has enough distinguishing features (being) 0,40 – 0,70 Fairly good An item in question

already has a fairly good differentiator 0,70 – 1,00 Good An item in question

already has an good differentiator.

Are negative Very bad Item in question different negative

power

They are five classification in item discrimination. They are bad, fairly bad, fairly good, good, very bad. Before we classify the result of item, we should count/examine the upper and lower group.

To know the discrimination, we should count it using the formula :

= � − � = � − �

The explanation as follows : Table 4.8

An Analysis of Item Discrimination

NO PA=

�

PB =

� 1 PA = ²³

26

= 0,88

PB = ²⁹

46

= 0,63

2 PA = ²³

26

= 0,88

PB = ³¹

46

= 0,67

3 PA = ¹⁷

26

= 0,65

PB = ²⁹

46

= 0,63

4 PA = ²⁰

26

= 0,77

PB = ²⁴

46

= 0,53

5 PA = ²²

26

= 0,85

PB = ³³

46

= 0,72

6 PA = ²³

26

= 0,88

PB = ²⁶

46

= 0,63

7 PA = ²⁵

26

= 0.96

PB = ³⁰

46

= 0,65

8 PA = ¹⁹

26

= 0,73

PB = ²⁸

46

= 0,61

9 PA = ²⁰

26

= 0,77

PB = ¹⁸

46

= 0,39

10 PA = ¹⁹

26

= 0,73

PB = ²⁷

46

= 0,59

11 PA = ¹⁹

26

= 0,73

PB = ²⁷

46

= 0,59

12 PA = ²⁰

26

= 0,77

PB = ¹⁹

46

= 0,41

13 PA = ²⁰

26

= 0,77

PB = ²⁴

46

= 0,52

14 PA = ²¹

26

= 0,81

PB = ³¹

46

= 0,67

15 PA = ¹⁸

26

= 0,69

PB = ²⁶

46

= 0,63

16 PA = ²³

26

= 0,88

PB = ³⁰

46

= 0,65

17 PA = ²²

26

= 0,85

PB = ³⁶

46

= 0,78

18 PA = ²¹

26

= 0,81

PB = ²⁷

46

= 0,59

19 PA = ²¹

26

= 0,81

PB = ²⁴

46

= 0,52

20 PA = ¹⁵

26

= 0,58

PB = ²⁵

46

= 0,54

21 PA = ¹⁸

26

= 0,69

PB = ²⁵

46

= 0,54

22 PA = ¹⁹

26

= 0,73

PB = ²⁹

46

= 0,63

23 PA = ¹⁸

26

= 0,69

PB = ²³ 46

= 0,5

24 PA = ²⁵

26

= 0,96

PB = ²⁶

46

= 0,63

25 PA = ²⁴

26

= 0,92

PB = ²⁸

46

= 0,61

26 PA = ¹⁸

26

= 0,69

PB = ²⁵

46

= 0,54

27 PA = ²¹

26

= 0,81

PB = ³¹

46

= 0,67

28 PA = ²³

26

= 0,88

PB = ²⁹

46

= 0,63

29 PA = ¹⁸

26

= 0,69

PB = ¹⁸

46

= 0,39

30 PA = ²¹

26

= 0,81

PB = ²⁶

46

= 0,63

31 PA = ¹⁹

26

= 0,73

PB = ²⁰

46

= 0,43

32 PA = ¹⁷

26

= 0,65

PB = ²²

46

= 0,48

33 PA = ²⁵

26

= 0,96

PB = ²⁶

46

= 0,63

34 PA = ¹⁹

26

= 0,73

PB = ¹⁹

46

= 0,41

35 PA = ²²

26

= 0,85

PB = ²⁵

46

= 0,54

36 PA = ¹⁵

26

= 0,58

PB = ²⁰

46

= 0,43

37 PA = ²⁴

26

= 0,92

PB = ³³

46

= 0,72

38 PA = ²²

26

= 0,85

PB = ²⁸

46

= 0,61

39 PA = ²⁰

26

= 0,77

PB = ²⁷

46

= 0,59

40 PA = ¹⁸

26

= 0,69

PB = ¹⁷

46

= 0,37

41 PA = ²¹

26

= 0,81

PB = ²⁸

46

= 0,61

42 PA = ²³

26

= 0,88

PB = ³²

46

= 0,69

43 PA = ²⁰

26

= 0,77

PB = ²⁴

46

= 0,52

44 PA = ²⁰

26

= 0,77

PB = ²¹

46

= 0,46

45 PA = ²²

26

= 0,85

PB = ²³ 46

= 0,5

46 PA = ²⁶

26

= 1

PB = ²⁸

46

= 0,61

47 PA = ²¹

26

= 0,88

PB = ²⁵

46

= 0,54

48 PA = ⁴⁸

26

= 0,88

PB = ²²

46

= 0,48

49 PA = ²²

26

= 0,85

PB = ²³ 46

= 0,5

50 PA = ²³

26

= 0,88

PB = ³³

46

= 0,72

To know the discrimination, we should count it using the formula :

= � − � = � − �

The explanation as follows : Table 4.9

An Analysis of Item Discrimination No P = correct answers

count of students D = PA – PB

Interpretation

1 D = 0,88 – 0,63 = 0,25 Fairly bad 2 D = 0,88 – 0,67 = 0,21 Fairly bad

3 D = 0,65 – 0,63 = 0,02 Bad

4 D = 0,77 – 0,52 = 0,25 Fairly bad

5 D = 0,85 – 0,72 = 0,13 Bad

6 D = 0,88 – 0,63 = 0,25 Fairly bad 7 D = 0,96 – 0,65 = 0,31 Fairly bad

8 D = 0,73 – 0,61 = 0,12 Bad

9 D = 0,77 – 0,39 = 0,38 Fairly bad

10 D = 0,73 – 0,59 = 0,14 Bad

11 D = 0,92 – 0,59 = 0,33 Fairly bad 12 D = 0,77 – 0,41 = 0,36 Fairly bad 13 D = 0,77 – 0,52 = 0,25 Fairly bad

14 D = 0,81 – 0,67 = 0,14 Bad

15 D = 0,69 – 0,63 = 0,06 Bad

16 D = 0,88 – 0,65 = 0,23 Fairly bad

17 D = 0,85 – 0,78 = 0,07 Bad

18 D = 0,81 – 0,59 = 0,22 Fairly bad 19 D = 0,81 – 0,52 = 0,29 Fairly bad

20 D = 0,58 – 0,54 = 0,04 Bad

21 D = 0,69 – 0,54 = 0,15 Bad

22 D = 0,73 – 0,63 = 0,1 Bad

23 D = 0,69 – 0,5 = 0,19 Bad

24 D = 0,96 – 0,63 = 0,33 Fairly bad 25 D = 0,92 – 0,61 = 0,31 Fairly bad

26 D = 0,69 – 0,54 = 0,15 Bad

27 D = 0,81 – 0,67 = 0,14 Bad

28 D = 0,88 – 0,63 = 0,25 Fairly bad

29 D = 0,69 – 0,39 = 0,3 Bad

30 D = 0,81 – 0,63 = 0,18 Bad

31 D = 0,73 – 0,43 = 0,3 Bad

32 D = 0,65 – 0,48 = 0,17 Bad

33 D = 0,96 – 0,63 = 0,33 Fairly bad 34 D = 0,73 – 0,41 = 0,32 Fairly bad 35 D = 0,85 – 0,54 = 0,31 Fairly bad

36 D = 0,58 – 0,43 = 0,43 Bad

37 D = 0,92 – 0,72 = 0,2 Bad

38 D = 0,85 – 0,61 = 0,24 Fairly bad

39 D = 0,77 – 0,59 = 0,18 Bad

40 D = 0,69 – 0,37 = 0,32 Fairly bad

41 D = 0,81 – 0,61 = 0,2 Bad

42 D = 0,88 – 0,69 = 0,19 Bad

43 D = 0,77 – 0,52 = 0,25 Fairly bad 44 D = 0,77 – 0,46 = 0,31 Fairly bad 45 D = 0,85 – 0,5 = 0,35 Fairly bad 46 D = 1 – 0,61 = 0,39 Fairly bad 47 D = 0,88 – 0,54 = 0,34 Fairly bad

48 D = 0,88 – 0,48 = 0,4 Bad

49 D = 0,85 – 0,5 = 0,35 Fairly bad

50 D = 0,88 – 0,72 = 0,16 Bad

Table 4.10

Classification of Item Discrimination

Classification No. Items Percent (%)

Bad 3,5,8,10,14,15,17,20,21,22,23,26,27,29, 30,31,32,36,37,39,41,42,48,50

48 % Fairly bad 1,2,4,6,7,9,11,12,13,16,18,19,24,25,28,

33,34,35,38,40,43,44,45,46,47,49

52 %

Fairly good - 0%

Good - 0%

Very bad - 0%

The result of the analysis in table 4.10 showed that the test consist of 52% items has fairly bad item discrimination, 48% items has bad item discrimination.

From table 4.10 showed percentage of fairly bad item dscrimination is high namely 52%. And this table also showed percentage of bad items lower then fairly bad items.