**Figure 2**:

In this Example 2.

The number of examinees was 25.

The number of test items is 40.

The highest and lowest scores were 33 and 13 respectively.

The class average (mean) (24.6) is more than the class median (25), distribution of examinee scores is skewed to the left. Despite this, examinee scores may show normal ball shape distribution.

The KR20 (Cronbach's alpha) is 0.74 which is an acceptable value for most of the authors. Such a value of internal consistency is suitable for class tests.

• Item 8: the difficulty index is 4.0% (difficult). It has negative discrimination power (DE = -0.17, Pbiserial = −0.06), one distractors is non-functional (C).

Comment: the correct answer is (A) while most of the examinees chose (B). According to distractor analysis, this item is miss-keyed rather than an implausible distractor.

• Item 9: the difficulty index is 20% (difficult). It has low discrimination power (DE = 0.17, Pbiserial = 0.09), all distractors are functional.

Comment: distractor analysis show option number (A) and (B) are more selected by examinees. This can be due to implausible. The presence of implausible can affect the item difficulty index. Distractors in this item should be revised or changed with plausible ones.

• Item 11: the difficulty index is 44.0% (moderate). It has low discrimination power (DE = 0.0, Pbiserial = 0.01) and only one the distractors is non-functional.

Comment: The item has an acceptable difficulty index. Distractor (D) is more selected by upper examinee such as the key answer. Such a situation can favor missed key or implausible distractors. The distractors need to be updated to have more efficiency.
