Dental-fillings data and population estimates

Dental-fillings data and population estimates

Secondary 2
11 marks
TGM Original Questions

The numbers of fillings recorded for 30 adults are: 2, 0, 4, 1, 3, 2, 1, 6, 0, 1, 5, 3, 2, 4, 1, 2, 0, 3, 6, 1, 4, 2, 3, 1, 0, 5, 2, 4, 3, 1.

  1. Draw a dot plot.[3]
  2. Find the mode, median and mean.[4]
  3. An adult is selected at random from these 30 adults. Find the probabilities that the adult has exactly 1 filling and from 2 to 5 fillings inclusive, respectively.[2]
  4. Estimate how many of 300 adults have no fillings.[2]

Solution:

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Answer:(a) completed dot plot with frequencies \(4,7,6,5,4,2,2\) (b) mode \(1\), median \(2\), mean \(2.4\) (c) \(\frac{7}{30},\frac{17}{30}\) (d) \(40\).

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