Dominic collected data on the location where students of two grades would most like to visit and displayed it on a table.

\begin{tabular}{|c|l|l|l|l|}
\hline & Aspen, Colorado & New York, New York & Chicago, Illinois & Total \\
\hline Under age 15 & [tex]$21\%$[/tex] & [tex]$16\%$[/tex] & [tex]$12\%$[/tex] & [tex]$49\%$[/tex] \\
\hline Age 15 and above & [tex]$17\%$[/tex] & [tex]$24\%$[/tex] & [tex]$10\%$[/tex] & [tex]$51\%$[/tex] \\
\hline Total & [tex]$38\%$[/tex] & [tex]$40\%$[/tex] & [tex]$22\%$[/tex] & [tex]$100\%$[/tex] \\
\hline
\end{tabular}

Which term best describes the entry of [tex]$24\%$[/tex]?

A. Marginal relative frequency
B. Marginal frequency
C. Joint relative frequency
D. Joint frequency



Answer :

To determine which term best describes the entry of 24%, we need to understand the concepts of the different types of frequencies in a contingency table:

1. Marginal Frequency: This refers to the totals in the margins of the table, which represent the sums of the rows or columns. In this table, examples of marginal frequencies are 49% (total percentage of students under age 15) and 51% (total percentage of students age 15 and above).

2. Marginal Relative Frequency: This is the relative frequency expressed as a percentage, and it is found in the same position as the marginal frequencies. For example, the marginal relative frequencies in the margins (totals of rows and columns) in this table are 49%, 51%, 38%, 40%, 22%, and 100%.

3. Joint Frequency: This refers to the specific counts or percentages in the cells of the table that represent the intersection of a particular row and a particular column. In this table, the individual entries like 21%, 16%, 17%, and 24% are joint frequencies.

4. Joint Relative Frequency: This term is used when the joint frequency is expressed as a percentage of the total. In this table, 24% is an example of a joint relative frequency because it represents the percentage of students aged 15 and above who would most like to visit New York, New York.

Given that 24% indicates the intersection of the "Age 15 and above" row and the "New York, New York" column, and it is expressed as a percentage of the total, the term that best describes the entry of 24% is:

Joint relative frequency.