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Flip to reveal answersHow do you estimate the mean of grouped data?
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All 9 Flashcards — Grouped data
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Question
How do you estimate the mean of grouped data?
Answer
Use Σfx ÷ Σf with x = the class midpoints.
Question
How do you find a class midpoint?
Answer
(lower boundary + upper boundary) ÷ 2.
Question
Why is the grouped-data mean only an estimate?
Answer
The exact values within each class are unknown, so midpoints are used to represent them.
Question
What is the modal class?
Answer
The class with the greatest frequency.
Question
What is the median class?
Answer
The class containing the (n/2)-th value, found from the running (cumulative) total.
Question
Are the modal class and median class always the same?
Answer
No — they are often different classes; find each separately.
Question
How do you find a missing frequency from a given mean?
Answer
Set Σfx ÷ Σf = the given mean (x = midpoints) and solve for the unknown frequency.
Question
What goes in the denominator of the estimated mean?
Answer
Σf, the total frequency.
Question
On Paper 2, how do you get the grouped mean quickly?
Answer
Enter the midpoints as the data list and the frequencies as the frequency list, then run 1-Var Stats.
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Full study notes for Grouped data
Topic 4.3 hub
Central tendency & spread
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Math AA SL exam skills
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