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Micky76
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Homework Statement
Question
Anna is calculating the mean and standard deviation for a set of data for a random
variable X. The data is summarised in the table below.
x: 10– 20– 30– 40–50
Frequency: 8 20 12 0
(i) For each of the following cases, write down the appropriate mid-values of the four
intervals.
(a) X is the weight of a letter, in grams. (This one is okay, variable is continuous)
(b) X is the number of misprints in a magazine. (This one is okay, variable discrete)
(c) X is the age, in complete years, of the audience at a cinema. (Problem)
Answers:
(a) 15, 25, 35, 45
(b) 14.5, 24.5, 34.5, 45
(c) 15, 25, 35, 45.5 (3 s.f.)
Homework Equations
The Attempt at a Solution
I understand a) and b) fine. However, I can't figure out c) since I can't figure out what type of variable it is. I initially thought it would be discrete, due to the number of *complete* years. Would that not make the answer the same as that to b) though?
Any clarification is greatly appreciated, exams coming soon :).