Methods2025 Exam 2 Section A · Q18CAS active1 mark

Comparing means of probability mass functions

Consider the following graphs, which represent probability mass functions.

Four probability mass function graphs. I: p(1)=0.1, p(2)=0.4, p(3)=0.4, p(4)=0.1, p(5)=0. II: p(1)=0.1, p(2)=0.2, p(3)=0.3, p(4)=0.4, p(5)=0. III: p(1)=0.45, p(2)=0.25, p(3)=0.15, p(4)=0.15, p(5)=0. IV: p(x)=0.2 for x=1,2,3,4,5.

Which pair of these probability mass functions has the same mean?

1 mark

AI and IIBI and IVCII and IIIDII and IV

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