The two-way table below gives data on the connection preferences available from a local cable company by floor.

[tex]\[
\begin{tabular}{|c|c|c|c|c|}
\hline
\multicolumn{5}{|c|}{Network Preference by Floor} \\
\hline
& First Floor & Second Floor & Third Floor & Total \\
\hline
Internet Only & 13 & 15 & 11 & 39 \\
\hline
Cable Only & 14 & 16 & 6 & 36 \\
\hline
Internet \& Cable & 11 & 9 & 22 & 42 \\
\hline
Total & 38 & 40 & 39 & 117 \\
\hline
\end{tabular}
\][/tex]

The marginal distribution for third-floor residents is 33.3%. What two numbers are used to make this distribution?



Answer :

Let's walk through the steps explicitly to understand the solution.

Given:
- The total number of residents on the third floor is 39.
- The marginal distribution for third floor residents is 33.3%.

We need to find the two numbers used to make this distribution. First, we interpret that the marginal distribution means that 33.3% of the total building’s residents live on the third floor. Now, let's break it down step by step:

1. Identify the total residents on the third floor: The total number of residents on the third floor is given as 39.

2. Convert the marginal distribution percentage to a decimal: The given marginal distribution for third floor residents is 33.3%. To work with this percentage in calculations, convert it to a decimal:
[tex]\[ 33.3\% = \frac{33.3}{100} = 0.333 \][/tex]

3. Calculate the total number of residents in the entire building: Given that 33.3% of the total residents live on the third floor, we can calculate the total number of residents (let's call this [tex]\( T \)[/tex]):
[tex]\[ \text{Total residents in the building} = \frac{\text{Third floor residents}}{\text{Marginal distribution third floor}} \][/tex]
Substituting the known values:
[tex]\[ T = \frac{39}{0.333} \][/tex]

4. Perform the division:
[tex]\[ T = \frac{39}{0.333} = 117 \][/tex]
So, the total number of residents in the entire building is 117.

5. Verify the number of third floor residents from this total: To ensure the calculation is correct, we need to verify this number. We know that 33.3% of the total residents live on the third floor:
[tex]\[ \text{Third floor residents} = 0.333 \times 117 \][/tex]
Performing the multiplication:
[tex]\[ 0.333 \times 117 = 39 \][/tex]

Thus, the two numbers used to make the marginal distribution are [tex]\( 39 \)[/tex] (the number of residents on the third floor) and [tex]\( 117 \)[/tex] (the total number of residents in the entire building).

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