Weighted index numbers (AQA GCSE Statistics): Flashcards
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What is a weighted index number?
What is a weighted index number?
It measures changes in items with different importance.
How do you calculate a weighted mean?
How do you calculate a weighted mean?
Use: Σ(value × weight) / Σweights.
What is the formula for the index number?
What is the formula for the index number?
Index = (current mean / base mean) × 100.
What does an index above 100 indicate?
What does an index above 100 indicate?
It shows an increase from the base year.
What is the weighted mean of A=£2.50, B=£2.80 with weights?
What is the weighted mean of A=£2.50, B=£2.80 with weights?
Weighted mean = (2.501000 + 2.802000) / 3000 = £2.67.
Calculate index number for 2017: Mean=£3.71, base=£2.71.
Calculate index number for 2017: Mean=£3.71, base=£2.71.
Index = (3.71 / 2.71) × 100 = 136.9.
What does a weighted mean represent?
What does a weighted mean represent?
It shows the average considering item importance.
Why is the base year index always 100?
Why is the base year index always 100?
It serves as a reference point for comparisons.
How to find percentage increase from index?
How to find percentage increase from index?
Subtract 100 from the index number.
What should you check in your weighted mean?
What should you check in your weighted mean?
It must fall between the smallest and largest values.