Classroom Notes: 2.1 Capturing Data

• Statistical Investigation: Knowing that it involves collecting data to answer a question.
• Data Types: How to collect categorical and discrete data.
• Computing Tools:
  • Data loggers (e.g., sensors recording temperatures every hour).
  • Spreadsheets (used to keep track of data such as expenses).
  • Databases (a collection of information, such as where people like to go on holiday).
  • Other productivity software (such as a word processor for writing up investigations).

• Identify different computing tools used in a statistical investigation.
• Explore how to plan a statistical investigation.
• Explore how to collect continuous data.
• Design an appropriate form to collect continuous data.

• Collaborate: Working together with other people on the same document at the same time.
• Continuous Data: Numerical data that can have any value (including fractions or decimals) and is not usually countable with your eyes.
• Criteria: Requirements needed when searching or filtering data.
• Questionnaire: A series of questions that you want to ask people.
• Question Type: The format or way in which a question is presented (e.g., short answer, multiple choice, ranking).
• Statistical Investigation: The collection of data to help find the answer to a question.
• Validation Rules: Restrictions applied to questions ensuring only specific types or formats of answers are accepted.

1. What do you want to find out? (e.g., what sort of pets classmates have).
2. What questions will help you find this out? (Questions must give exact information; decide whether to provide set choices or allow free answers).
3. Who will you ask? (Needs to be specific: "Which pets do people in my class have?" is specific; "Which pets do people have?" is not).
4. How will you collect the data? (Use questionnaires for opinions/favourites; use data loggers and spreadsheets for automated readings like temperature).
5. How will you analyse the data? (Represent and review results using suitable charts or graphs).

• Data Loggers: Devices using sensors to collect continuous data automatically over time.
  • Benefits: Operates without human assistance; can be placed in hazardous or remote locations (e.g., Antarctica, volcanoes).
  • Applications: Weather stations (recording hourly temperature and wind speed), science labs (testing acid levels in drinks, investigating voltage vs. volume), sports lessons (heart rate monitoring), and seismographs (recording earthquakes).
• Spreadsheets: A digital document with cells arranged in rows and columns (like Excel or Google Sheets) used to store data, performs mathematical operations (* for multiplication, / for division, addition, subtraction, averages), and visually display data via charts or graphs.
• Databases: A database is a systems used for storing, organising, searching, and filtering data according to criteria. Some database software includes Microsoft Access.
• Word Processors: Software used to write reports or produce question sheets, which includes automatic spelling checks and easy sharing via email or printing.
• Online Forms / Questionnaires: Tools like Google Forms used to gather responses digitally over the web without printing paper copies. Responses are automatically arranged and collated into a spreadsheet.

When designing a form to record continuous data, apply the following design rules:

• Precise Phrasing: State the exact conditions. For example, use "What was the temperature in your classroom at 12:00 p.m. on Monday?" instead of "What is the temperature?".
• Frequency & Time Period: State clearly how often (e.g., three times a day) and over what period (e.g., daily for a week) measurements must be recorded.
• Units of Measurement: Specify the expected unit (e.g., mm, cm, kg, lb).
• Precision / Decimal Requirements: Specify how many digits are required after the decimal point (e.g., one or two decimal places).