Mean for difficulty index discrimination index and distractor efficiency were 383 027 and 828 respectively. Of 30 items 11 items were of higher difficulty level DIF I 60.
Calculating Difficulty Discrimination And Reliability Index Standard Error Of Measurement Ppukm
Too Difficult.
How to calculate discrimination index. A highly discriminating item indicates that the students who had high tests scores got the item correct whereas students who had low test scores got the item incorrect. Then calculate the Average Discrimination Index by typing command such as AVERAGE B25AE25 at the very last column cell AF25 as what is illustrated below. The range of this index is 1 to -1.
D sqrt 1r 1-r The square root is in the formula to return the value to the original units of the. Calculating Difficulty and Discrimination Top scoring group n 25. The item was flawed or miskeyed.
Discrimination power RU-RLNUorNL The procedure involves the following steps. Arrange the students who took the test in descending order according to their total score on the test. Wheeler defines the discrimination ratio as.
W G ìXî Acceptable 021-024 Good 025-035 Æ oo v HìXïò n11 n34 n5 n15. Calculating the Average Discrimination Index. Then divide by the number of students in each group in this case there are five in each group.
Total 15 items. For each item count the number of students in the. Sum the differences To calculate.
Item discrimination can be calculated by ranking the students according to total score and then selecting the top 27 percent and the lowest 27 percent in terms of total score. Subtract 60 20 40 for a DI of 40 Score group Upper n 25 Middle n 50 Lowern 25 Itemnumber np np np 2156030 520 Item 3. Wood 1960 stated that.
Categorization of MCQs according to difficulty index n65 17 8 23 52. All students got the item right. The Discrimination Index D is computed from equal-sized high and low scoring groups on the test.
The discrimination index D is the number of people in the upper group who answered the item correctly minusthe number of people in the lower group who answered the item correctly dividedby the number of people in the largest of the two groups. 38 got it correct. Subtract the number of successes by the low group on the item from the number of successes by the high group and divide this difference by the size of a group.
The difficulty is given by Df SUM B4B21COUNT B4B21 1118 611. Divide the students into three sections - the upper group the middle group and the lower group - based on their scores. There are several different formulas that calculate item discrimination but the one that is most commonly used is called the point-biserial correlation which compares a test takers score on an individual item with their score on the test overall.
Calculating Discrimination Index using Microsoft Excel. Categorization of MCQs according to discrimination index n65. It gives a rough idea of how students performed as a whole.
Figure 1 Item Analysis. Calculate the differences Next fill in the Diff row by completing the difference between the Actual and Rearr. You then take the number of candidates from the lower group who got the item correct away from the number of candidates from the upper group who got the item correct divide by the number of candidates in a group and you will get a number between -1 and 1.
Discrimination index D scale. 040 and above very good item 030 - 039 reasonably good item but possibly subject for improvement 020 029 marginal item subject to improvement Below 020 poor item to be rejected or revised. Since 5 of the top 6 students got question 1 right and 2 of the bottom 6 got the question right the discrimination index D 56 26 36 5.
The difference is one measure of item discrimination IDis. 24 got it correct or 96 Middle group n 50. This is the discrimination index for the item.
Discrimination power is estimated using the following formula. Transposing the Difficulty and Discrimination Index for Analysis. Of course if you have sophisticated exam software such as Maxexam then it will.
Discrimination Index Interpretation 030 and above Good 010 030 Fair Equal to 0 No discrimination. Discrimination of the item is. The mean score is the average of the test scores for the class.
For each item the percentage of students in the upper and lower groups answering correctly is calculated. Determine the Discrimination Index by subtracting the number of students in the lower group who got the item correct from the number of students in the upper group who got the item correct. Calculating the DI Fill in the Rearr row First rearrange the Actual scores so that they are in ideal increasing order.
