Mr. and Mrs. Jones live in a neighbourhood where the mean family income is $45,000 with a standard deviation of $9,000. Mr. and Mrs. Smith live in a neighbourhood where the mean is $100,000 and the standard deviation is $30,000. What are the relative dispersions of the family incomes in the two neighbourhoods?
A) Jones 40%, Smith 20%
B) Jones 20%, Smith 30%
C) Jones 30%, Smith 20%
D) Jones 50%, Smith 33%

Question

Quizplus · Accepted Answer

The relative dispersion, or coefficient of variation, is calculated as (standard deviation / mean) * 100%. For the Jones' neighbourhood: (9000 / 45000) * 100% = 20%. For the Smiths' neighbourhood: (30000 / 100000) * 100% = 30%.

Mr and Mrs