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Time series and index numbers

2 dot points across 2 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do index numbers measure change over time, and how are the RPI, CPI and a weighted index used and interpreted?

Calculate and interpret simple index numbers, understand the Retail Prices Index and Consumer Prices Index, find a weighted index number, and use a chain base to compare year-on-year change.
A CCEA GCSE Statistics answer on index numbers: simple price and quantity index numbers, the base year, the Retail Prices Index and Consumer Prices Index, weighted index numbers, and the chain base method.
11 min answer →

How do you analyse data over time using a time series, moving averages and a trend line, allowing for seasonal variation?

Plot and interpret a time series, calculate moving averages to smooth the data, plot and use a trend line, identify seasonal variation, and use the trend to make predictions.
A CCEA GCSE Statistics answer on time series: plotting a time series, calculating moving averages to smooth fluctuations, plotting a trend line, identifying seasonal variation, and using the trend to predict.
11 min answer →