this sample predicts, with 90% confidence, that the real mean improvement in ATAR scores from this course for all Melbourne high school students is 81.85 points with margin of error 9.55 points.

there is a 90% chance that the real mean improvement in ATAR scores from this course for all Melbourne high school students is between (72.3, 91.4) points.

If we construct 100 confidence intervals for mean improvement in ATAR scores in the same way described above, each based on a random sample of eighty-five students, about 90 of these intervals will contain the real mean improvement in ATAR scores.

this sample predicts, with 90% confidence, that all Melbourne high school students who take the course have their ATAR scores improved by between 72.3 and 91.4 points on average.