To solve this problem, we need to perform a linear regression analysis on the given data to find the slope and intercept of the best-fit line. This will allow us to interpret the relationship between the number of messages sent and received.
- Extract the data from the table.
- Use a linear regression model to find the slope and intercept.
- Interpret the slope and intercept based on the regression results.
We are given a table of messages sent and received. Let's denote the number of messages sent as \( x \) and the number of messages received as \( y \).
\[
\begin{array}{cc}
\text{Sent} & \text{Received} \\
2 & 6 \\
0 & 1 \\
78 & 81 \\
67 & 69 \\
150 & 152 \\
3 & 3 \\
225 & 230 \\
325 & 328 \\
5 & 8 \\
4 & 6 \\
0 & 4 \\
2 & 5 \\
10 & 13 \\
3 & 7 \\
6 & 8 \\
6 & 7 \\
6 & 7 \\
3 & 4 \\
5 & 9 \\
62 & 66 \\
\end{array}
\]
To find the slope (\( m \)) and intercept (\( b \)) of the linear regression line \( y = mx + b \), we use the formulas:
\[
m = \frac{n(\sum xy) - (\sum x)(\sum y)}{n(\sum x^2) - (\sum x)^2}
\]
\[
b = \frac{(\sum y)(\sum x^2) - (\sum x)(\sum xy)}{n(\sum x^2) - (\sum x)^2}
\]
Where \( n \) is the number of data points.
First, we compute the necessary summations:
\[
\sum x = 957, \quad \sum y = 1008, \quad \sum x^2 = 204,073, \quad \sum y^2 = 213,204, \quad \sum xy = 214,073
\]
Substitute the summations into the slope formula:
\[
m = \frac{20(214,073) - (957)(1008)}{20(204,073) - (957)^2}
\]
\[
m = \frac{4,281,460 - 964,656}{4,081,460 - 915,849}
\]
\[
m = \frac{3,316,804}{3,165,611} \approx 1.0478
\]
Substitute the summations into the intercept formula:
\[
b = \frac{(1008)(204,073) - (957)(214,073)}{20(204,073) - (957)^2}
\]
\[
b = \frac{205,716,984 - 204,872,961}{4,081,460 - 915,849}
\]
\[
b = \frac{844,023}{3,165,611} \approx 0.2666
\]
The slope \( m \approx 1.0478 \) indicates that for each additional message sent, there is an average of 1.048 more messages received.
The intercept \( b \approx 0.2666 \) indicates that with 0 messages sent, there should be about 0.267 messages received.
\[
\boxed{m \approx 1.0478}
\]
\[
\boxed{b \approx 0.2666}
\]
\[
\boxed{\text{A. For each additional message sent, there is an average of } 1.048 \text{ more messages received.}}
\]
\[
\boxed{\text{A. With 0 messages sent, there should be about } 0 \text{ message(s) received.}}
\]