Which statement about a joint relative frequency is true? A group of youths at an international conference were surveyed to determine their primary language.

Question

Use the following information and the table to answer the question. A group of youths at an international conference were surveyed to determine their primary language.

The results appear in the following relative frequency table.

Spanish German Chinese Total

Girls 25% 16% 9% 50%

Boys 19% 24% 7% 50%

Total 44% 40% 16% 100%

Which statement about a joint relative frequency is true?

A) Of all students surveyed, 9% are girls who speak primarily Chinese.

B) Of all students surveyed, 16% speak primarily Chinese.

C)Of the boys surveyed, 48% speak primarily German.

D)Of all students surveyed, 50% are girls.

I was thinking either B or D?

Answer 1

Hi Klauss,

The "joint" frequencies are found in the body of the table and always involve one of each of the independent variables such as the percentage of boys who speak german=24% In this case it a statement about a "join" condition "Boys and German"

The percentages found in the totals row and column are called "marginal" frequencies and only involve one variable such as 16% speak primarily Chinese.

With this in mind if we look at the choices:

A. Is a statement about joint frequencies (girls and Chinese) and is true ie found in the table

B Is a statement about marginal frequencies about Chinese and is true

C. Is a statement about joint frequencies (boys and German) but it's not true it's really 24%

D. Is a statement about marginal frequencies about girls and is true.

I think that choice A. is the correct answer. Agree?

Hope this helps

Jim