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. Then,
divide by the number of students in each group
(in this case, there are five in each group).
What is the item discrimination index?
Discrimination Index – The discrimination index is
a basic measure of the validity of an item
. It is a measure of an item’s ability to discriminate between those who scored high on the total test and those who scored low.
What is item difficulty and item discrimination?
So item difficulty helps us to know the degree to which students get answers correct, whereas item discrimination
examines how the top-scoring group of test takers compares to the lowest-scoring group of test takers
, another important piece of information to help us know how well our items are working.
What is the difference between item discrimination and item difficulty in what ways are these measures valuable in the evaluation of a test Why?
So
item difficulty helps us to know the degree to which students get answers correct
, whereas item discrimination examines how the top-scoring group of test takers compares to the lowest-scoring group of test takers, another important piece of information to help us know how well our items are working.
What is Item discrimination in item analysis?
Item discrimination refers
to the ability of an item to differentiate among students on the basis of how well they know the material being tested
. Various hand calculation procedures have traditionally been used to compare item responses to total test scores using high and low scoring groups of students.
How do you calculate item difficulty and item discrimination?
Count the total number of students answering each item correctly
. For each item, divide the number answering correctly by the total number of students. This gives you the proportion of students who answered each item correctly. This figure is called the item’s difficulty level.
What is discrimination formula?
The Discrimination Index (D) is computed from equal-sized high and low scoring groups on the test. 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 range of this index is +1 to -1.
How do you solve discrimination index?
The Discrimination Index (D) is computed from equal-sized high and low scoring groups on the test. 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 range of this index is +1 to -1.
What does a discrimination index of 1 mean?
“1”
indicates the answer was correct
; “0” indicates it was incorrect. Follow these steps to determine the Difficulty Index and the Discrimination Index. After the students are arranged with the highest overall scores at the top, count the number of students in the upper and lower group who got each item correct.
What is the discrimination level?
The discrimination index of an item is
the ability to distinguish high and low scoring learners
. The closer this value is to 1, the better the item distinguishes the learners who get a high score from those who get a low score.
What does high discrimination index mean?
Discrimination Index – The discrimination index is a basic measure of the validity of an item. It is a
measure of an item’s ability to discriminate between those who scored high on the total test
and those who scored low.
What are the steps in items analysis?
- award of a score to each student.
- ranking in order of merit.
- identification of groups: high and low.
- calculation of the difficulty index of a question.
- calculation of the discrimination index of a question.
What is the relationship between validity and reliability?
Reliability (or consistency) refers to the stability of a measurement scale, i.e. how
far it will give the same results on separate occasions
, and it can be assessed in different ways; stability, internal consistency and equiva- lence. Validity is the degree to which a scale measures what it is intended to measure.
What is Miskeyed item?
(ˌmɪsˈkiː) vb (tr) to key (something) incorrectly on
a keyboard
.
How do you calculate optimal item difficulty?
Determine the Difficulty Index by
dividing the number who got it correct by the total number of students
.
What is difficult Index?
The Difficulty Index is
the proportion or probability that candidates, or students, will answer a test item correctly
. Generally, more difficult items have a lower percentage, or P-value.
