Data Explorer

How does the state use the confidence interval?

Since the accuracy of measures of student performance depend on the number of students participating in the assessments (the more students; the more accurate), the state uses a statistical test to take into account the number of students participating. The relationship is shown in the graphs.

In reading the red horizontal line represents the annual measurable objective (AMO) in for a school that has grades 3, 4, and 5.

In mathematics the red horizontal line represents the annual measurable objective (AMO) for a school that has grades 3, 4, and 5.

The X-axis represents groups of different sizes for the number of students participating in the assessment. The Y-axis represents the percentage of students scoring at the proficient level. The blue lines represent the confidence interval for each group size. You can see that the more students you have in a group, the smaller the blue line (the confidence interval). Scores falling on the blue line are statistically equal to the AMO.

Since we are only interested in whether a school met the AMO and not if they exceeded it, we focus on whether the score is below the blue line (outside the confidence interval). Scores below the blue line are statistically significantly less than the AMO and therefore, we conclude that the school performance is significantly below the target.