Data: Its Source and Compilation
Class 12 · Geography
4 ideas in Class 12 Geography, explained in plain words, with games and quizzes to practise.
Data, Information and the Need
Part of: Data and Its Sources
Data are numbers that measure the real world; one single measure is a datum, while a useful answer drawn from many measures is information. Tables and maps of crops, people and trade all rest on data. Averages can trick: a river averaging 0.95 m hid a 1.5 m pit that drowned a small child, a warning called statistical fallacy. Good collection plus honest presentation turns heaps of figures into true insight, shifting study from mere words to measured proof.
Why it matters. Every claim about crops, cities or rains leans on data. Knowing what data are and how averages cheat helps you read reports without being fooled.
Key words
- data
- : Numbers that measure happenings of the real world.
- datum
- : One single measurement from the real world.
- information
- : A useful answer drawn from many measures.
- statistical fallacy
- : A wrong reading caused by trusting averages blindly.
Try it in two minutes
- Note today's temperature and rain from a bulletin.
- Ask what one reading proves and what it hides.
- Ask which further figures would complete the picture.
Try at home. Record your home's water use for a week and turn the list into one clear line of advice.
Primary and Secondary Sources
Part of: Data and Its Sources
Primary data are gathered first-hand: watching land and people in the field with trained eyes, interviewing locals with clear aims and polite simple speech, writing tick-box quizzes that respondents fill themselves, or sending trained counters with schedules for those who cannot read. Kits and sensors add soil, water and crop readings. Secondary data come second-hand: ministry and census reports, city and district plans, world agency yearbooks, private studies, dailies, the net, plus unpublished files like village land rolls and council papers.
Why it matters. Every table stands on one of these legs. Knowing each source's reach and limit helps you trust, check and cite figures wisely.
Key words
- primary sources
- : Data caught first-hand by watching and asking.
- secondary sources
- : Data borrowed from published or filed records.
- questionnaire
- : Tick-box quiz filled by the respondent alone.
- schedule
- : Quiz filled by a trained counter asking aloud.
- enumerator
- : Trained counter who fills schedules in the field.
Try it in two minutes
- Ask who counted the figures in a textbook table.
- Ask if they watched, asked, or copied them.
- Ask who could check them again.
Try at home. Survey ten neighbours with three tick-box queries and tally the replies.
Tables, Ratios and Index Numbers
Part of: Compiling and Presenting
Raw heaps must be tamed into tables: neat rows and columns that ease finding and comparing. Figures may stay absolute counts, turn into shares per hundred, or become index numbers. A share per hundred divides a part by the whole and scales to 100, as in literacy rates. An index tracks change against a base year set at 100: divide the later total by the base total and scale to 100. Thus output rising from 32.5 to 42.2 reads 130, and to 67.4 reads 207.
Why it matters. Tables, shares and indices are the grammar of reports. Reading them lets you compare lands and years fairly instead of drowning in raw heaps.
Formulas
- Share per hundred = (part / whole) x 100
- Index = (current total / base total) x 100
- Base year index = 100
Key words
- raw data
- : Unordered heaps of collected figures.
- statistical table
- : Neat rows and columns easing finding and comparing.
- percentage
- : A share per hundred of a whole.
- index number
- : Change scored against a base year fixed at 100.
- base year
- : The starting year fixed at 100 for comparing.
Try it in two minutes
- List runs scored by two players across three games.
- Turn each total into a share per hundred balls.
- Set game one at 100 and index the later games.
Try at home. Index your monthly pocket money against January set at 100.
Grouping into Frequencies
Part of: Compiling and Presenting
Long mark lists shrink into ten-unit classes, from 0-10 up to 90-100. Tallies count heads per class by the four-and-cross method. The headcount per class is the simple frequency f, and all f sum to N, here 60. Running totals give cumulative frequency: less-than counts pile upward to a rising curve, more-than counts pile downward to a falling curve. In exclusive classes a border mark joins the higher class; in inclusive classes borders sit apart, as in 50-59.
Why it matters. Grouped tables reveal where crowds of scores gather. Reading f and running totals lets you answer how many passed, failed or topped in seconds.
Formulas
- N = sum of all frequencies
- Cumulative frequency = sum of all frequencies up to that class
Key words
- frequency
- : Headcount of individuals falling in one class.
- cumulative frequency
- : Running total piled up to a class.
- exclusive classes
- : Border marks join the higher class only.
- inclusive classes
- : Classes with borders set apart, as 50-59.
- ogive
- : Curve of cumulative frequencies, rising or falling.
Try it in two minutes
- List ten family ages on slips.
- Sort them into ten-year classes.
- Tally each class and pile running totals.
Try at home. Group your class test marks into ten-unit classes and find the busiest class.
What your child will practise
- Data, Information and the Need: Space Quick Fire (Quick Fire)
- Grouping into Frequencies: Candy Puzzle (Clue Puzzle)
- Grouping into Frequencies: Ocean Quick Fire (Quick Fire)
- Primary and Secondary Sources: Jungle Quick Fire (Quick Fire)
- Tables, Ratios and Index Numbers: Space Puzzle (Clue Puzzle)
- Quiz: Data, Information and the Need (8 questions)
- Quiz: Grouping into Frequencies (8 questions)
- Quiz: Primary and Secondary Sources (8 questions)
- Quiz: Tables, Ratios and Index Numbers (8 questions)