Loading the lesson
Loading the lesson
Search AllRounder.ai
Search the courses, subjects, tracks, games and features, or jump straight to a page.
Search the courses, subjects, tracks, games and features, or jump straight to a page.
5 cards from this section. Quick, good the night before a test.
Write down the midpoints of the classes 10–20, 20–30 and 30–40.
Add the two boundaries and halve the result.
The classes 10–20, 20–30 and 30–40 have frequencies 4, 10 and 6. Estimate the mean.
Multiply each midpoint by its frequency, add, then divide by the total frequency.
What is the midpoint of the class 20–30?
Halve the sum of the boundaries.
Estimate the mean of the grouped marks 0–10 (2), 10–20 (3), 20–30 (5).
Divide Σfx by Σf.
A class of 50 students has marks grouped as 0–20 (5), 20–40 (10), 40–60 (15), 60–80 (12) and 80–100 (8). Estimate the mean and standard deviation.
Keep the deviations to one decimal place exactly; do not round until the end.
Group A has marks 0–10 (2), 10–20 (3), 20–30 (5). Group B has marks 0–10 (5), 10–20 (0), 20–30 (5). Find the estimated mean and standard deviation of Group B and compare the spread of the two groups.
Classes with zero frequency contribute nothing to the sums.
6 more questions in this section. Enroll free to practise them all.
Enroll free