Exercise Set 7.1

  1. Rank the following events on a scale from 0 (Impossible) to 1 (Certain). Label each event: Impossible, less likely, equally likely (even chance), more likely, certain. Give reasons why you gave each event its ranking.
    (i) The next Monday will come after Sunday.
    (ii) It will snow in Mumbai in July.
    (iii) An elephant will walk through your classroom today.
    (iv) You will greet at least one friend at school tomorrow

    Solution:
    (i) Ranking: 1
    Label: Certain
    Reason: The days of the week always follow the same order. Sunday is always followed by Monday.

    (ii) Ranking:     0
    Label: Impossible
    Reason: Mumbai has a hot and humid climate, and July is the rainy (monsoon) season. Snowfall does not occur there.

    (iii) Ranking:     0
    Label: Impossible
    Reason: Elephants are wild animals. They are found in forests, wildlife sanctuaries, or zoos. They do not live or roam around schools.

    (iv) Ranking:     0.8 or 0.9
    Label: More likely
    Reason: Most students meet and greet their friends at school every day, so this is very likely, though not absolutely certain (for example, if the student is absent)