Answer: Tammy's sample may not be vaild because she surveyed the students only from her class and it is likely that other classes might not like the subject maths. She might get the accurate results by surveying a larger number of people in the school instead of just her class.
Answer:
The Domain of the graph is all real numbers less than or equal to 0.
A scatter diagram has points that show the relationship between two sets of data.
We have the following data,

where <em>x</em> is the average number of employees in a group health insurance plan and <em>y</em> is the average administrative cost as a percentage of claims.
To make a scatter diagram you must, draw a graph with the independent variable on the horizontal axis (<em>in this case x</em>) and the dependent variable on the vertical axis (<em>in this case y</em>). For each pair of data, put a dot or a symbol where the x-axis value intersects the y-axis value.
Linear regression is a way to describe a relationship between two variables through an equation of a straight line, called line of best fit, that most closely models this relationship.
To find the line of best fit for the points, follow these steps:
Step 1: Find
and
as it was done in the below table.
Step 2: Find the sum of every column:

Step 3: Use the following equations to find intercept a and slope b:

Step 4: Assemble the equation of a line
