3.1 Statistics 1I

• collect data from the immediate environment
• group and represent the data in a frequency distribution table
• determine mean, mode and median of grouped data
• present grouped data using histograms
• apply measures of central tendency in real life situations
• embrace the use of measures of central tendency in everyday life

“Why is data collection important in day to day life?”

“How are measures of central tendency applicable in real life?”

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1. Why we collect data
   40 min · 1 practice tasks · quiz
   Explain primary and secondary data, a population and a sample, and how data is gathered.
2. Tally and frequency
   40 min · 1 practice tasks · quiz
   Record raw data with tally marks and build an ungrouped frequency table.
3. Grouping into classes
   40 min · 1 practice tasks · quiz
   Find the class limits, width, boundaries and midpoint of grouped data.
4. A grouped frequency table
   40 min · 1 practice tasks · quiz
   Build a grouped frequency table with tally, frequency and a checked total.
5. Histograms
   40 min · 1 practice tasks · quiz
   Draw and read a histogram for grouped data with uniform classes.
6. Frequency polygons
   40 min · 1 practice tasks · quiz
   Draw a frequency polygon at the class midpoints and compare two data sets.
7. The mean from midpoints
   40 min · 1 practice tasks · quiz
   Find the mean of grouped data using the class midpoints.
8. More mean practice
   40 min · 1 practice tasks · quiz
   Find and interpret the mean of grouped data for a second set.
9. The assumed mean method
   40 min · 1 practice tasks · quiz
   Use an assumed mean to find the mean of grouped data with smaller numbers.
10. Choosing a working mean
    40 min · 1 practice tasks · quiz
    Choose a good assumed mean and use the coded method with the class width.
11. The modal class
    40 min · 1 practice tasks · quiz
    Identify the modal class from a grouped frequency table.
12. Estimating the mode
    40 min · 1 practice tasks · quiz
    Estimate the mode inside the modal class by interpolation.
13. Cumulative frequency
    40 min · 1 practice tasks · quiz
    Build a cumulative frequency column and find the median class.
14. The median of grouped data
    40 min · 1 practice tasks · quiz
    Find the median of grouped data by interpolation.
15. More median practice
    40 min · 1 practice tasks · quiz
    Find the median of grouped data for a second set and interpret it.
16. Which average to use?
    40 min · 1 practice tasks · quiz
    Compare the mean, median and mode and choose the right one for a question.
17. When the mean misleads
    40 min · 1 practice tasks · quiz
    Show how one extreme value drags the mean away from the median.
18. The mean of two groups
    40 min · 1 practice tasks · quiz
    Find the mean of two groups combined from their separate means and sizes.
19. Adding or removing a value
    40 min · 1 practice tasks · quiz
    Find the new mean after a value is added to or removed from a data set.
20. Choosing the class size
    40 min · 1 practice tasks · quiz
    Choose sensible classes for a set of data and see how the choice affects the picture.
21. Application: test marks
    40 min · 1 practice tasks · quiz
    Use the mean, median and modal class to report on a set of examination marks.
22. Application: community data
    40 min · 1 practice tasks · quiz
    Analyse waiting times at a clinic and advise on the busiest period.
23. Application: farm and business
    40 min · 1 practice tasks · quiz
    Analyse milk yields and choose the average that suits the decision.
24. A group data project
    40 min · 1 practice tasks · quiz
    Plan and carry out a small survey, then present the grouped results.
25. Statistics: mixed review
    40 min · 1 practice tasks · quiz
    Bring together tables, the mean, the median, the mode and the histogram.