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Topic: Collecting Data (Higher - Unit 1)

Specification References: S5.9

S5.9 Understand that increasing sample size generally leads to better estimates of probability and population characteristics.


Candidates should be able to:

  • understand that the greater the number of trials in an experiment the more reliable the results are likely to be
  • understand how a relative frequency diagram may show a settling down as sample size increases, enabling an estimate of a probability to be reliably made; and that if an estimate of a probability is required, the relative frequency of the largest number of trials available should be used

Notes

Refer also to S5.7 and S5.8.

Examples

  1. From a relative frequency diagram:
    Use the diagram to make the best estimate of the probability of picking a red disc.

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  1. Aisha catches 10 frogs at random from a pond and measures their weight.
    She then uses the data to estimate the mean weight of a frog in the pond.
    How could she obtain a more reliable estimate for this mean?

  2. The table shows the number of heads obtained in every 10 flips of a coin.

    Trials 1st 10 2nd 10 3rd 10 4th 10 5th 10
    Number
    of heads    		 3 2 2 1 2

    Draw a relative frequency graph for this data (graph paper available)
    Use your graph or otherwise obtain an estimate of the probability of a head for this coin.