Point Biserial - A measurement of the discrimination of an item. It indicates the relationship between a response for a given item and the overall test score of the respondent. The point biserial tells you if a question was a good discriminator between the better students and the poorer students. Point biserial ranges from -1 to 1. A positive value indicates that the students who did well on the test answered the question correctly.

Range of scores - distance between the highest and lowest score

Standard deviation - measure of the dispersion of a set of data from its mean. The more spread apart the data is, the higher the deviation. It is calculated by taking the square root of the variance.

Variance - The amount that each score deviates from the mean squared (by multiplying it by itself).

Percentiles

25th Percentile - 25 percent of the data values lie below the 25th percentile

Median score

75th percentile - 25 percent of the data values lie above the 75th percentile

Inter Quartile Range - The difference between the 75th percentile and the 25th percentile

Confidence Intervals (1, 5, 95, and 99%)

Test Reliability

Kuder-Richardson Formula 20 & Kuder-Richardson Formula 21 - These formulas measure test reliability and are an overall measure of internal consistency. A higher value indicates a stronger relationship between items on the test.

Coefficient (Cronbach) Alpha - A coefficient that describes how well a group of items focuses on a single idea or construct.

Provides some overall statistics and then provides statistics on individual questions:

Overall

Total possible points

Total students

Standard deviation

Median score

Mean score

Reliability Coefficient (KR20) - a higher value indicates a stronger relationship between items on the test

Maximum score

Minimum score

Range of scores -- difference between max and min

Question Statistics

Correct answer

Response frequencies (percentages)

Non distractor (question choices not selected by students)

Correct group responses - The TOTAL% column displays the percentage of students who answered the question correctly. The UPPER 27% column displays the percent correct for the individual question based on the students who scored in the upper 27% for the test as a whole. The LOWER 27% column displays the percent correct for the individual question based on the students who scored in the lower 27% for the test as a whole.

Point Biserial -- A measurement of the discrimination of an item. It indicates the relationship between a response for a given item and the overall test score of the respondent. The point biserial tells you if a question was a good discriminator between the better students and the poorer students. Point biserial ranges from -1 to 1. A positive value indicates that the students who did well on the test answered the question correctly.