# Line of Best Fit Worksheets

We will often work with scatter plots to understand if two completely different share any type of relationship. To do this we first plot the data that we have collected. This data will result in a bunch of different points being plotted all over the coordinate graph. We can line draw a line of best fit by simply eyeballing the graph and drawing a straight line that splits all the data points into two equal parts. This means that the number of data points above and below the line that we have drawn are equal. You will often hear this referred to as a trend line because it tells us the general direction that series of data points follow. This helps us understand the nature of relationship that exists between the two variables. These worksheets and lessons help students make sense of data by predicting trends and relationships that exist with the data.

### Aligned Standard: Grade 8 Statistics & Probability - 8.SP.A.2

- Cost and Number of Sales Step-by-Step Lesson- The outcome of this defies logic, but then again data has been known to do that at times.
- Guided Lesson - Find the relationships displayed between : The amount of cheese on pizzas and price, the salary of employees and the amount they spend, and tax increases and inflation.
- Guided Lesson Explanation - This is where students start to finally realize that math has a real purpose in life.
- Independent Practice - A nice obstacle course of problems that are spread over three pages.
- Matching Worksheet - Match the graph to the data tables that they illustrate.
- Scatter Plots and Line of Best Fit Five Pack - This is one of my most used five packs on the site.

- Answer Keys - These are for all the unlocked materials above.

### Homework Sheets

Creating graphs is one of the best ways to see relationships within data sets.

- Homework 1 - So, this graph indicates a steadily falling line of best fit. This indicates a negative relationship between price of items and number of items sold.
- Homework 2 - This indicates a positive relationship between the tax and deflation. As the tax rate decreases, deflation percentage increases.
- Homework 3 - This indicates a negative relationship between the temperature and latitude because as the latitude increases, the average temperature decreases.

### Practice Worksheets

We give you sets of data and ask you to identify the relationship, if one exists at all.

- Practice 1 - Is there any relationship between the average hours of studying and scores on exams?
- Practice 2 - Is there any relationship between the sale of locks and the sale of keys?
- Practice 3 - Is there any relationship between the number of wall clocks and wrist watches a brand makes?

### Math Skill Quizzes

These are the most common types of questions that you will see for this content.

- Quiz 1 - The table lists the sale of cosmetics from the year 1999 to 2013. Sketch a scatter plot of the data.
- Quiz 2 - The table lists the population of a town from the year 1989 to 1991. Predict the population based in year 1989.
- Quiz 3 - What type of correlation does this graph show?

### How Can You Use the Line of Best Fit?

Most of the time, when we must determine a relationship between two quantities, we use different graphs to illustrate the relationship. As simple as it may sound, straight lines can actually work for many quantities to demonstrate the relationship. In this sense we are not attempting to uncover a great deal about this association between the two variables, we just want to understand if one has an effect on the other or it is even good to know when they do not have a relationship at all.

When we have a problem involving two quantities, we look to find a hidden relationship between them. We determine either a relationship exists between the quantities or not. In case the variables are linearly related to each other, you can use a straight line to demonstrate their relationship on a graph. Use the line equation to find out the values of the two variables (x and y).

For example, you have a straight-line equation: y = 23.5 + 2.45x

This equation is used to define the relationship between the length of a shoe length and the height of a person. Here x represents shoe length, and y represents the height. To find out the height of the man who has a shoe size 10, substitute the value 10 for x in the equation and predict the value of y.

Plot the points on the graph. A rising line indicates a positive relationship between the variables, whereas a tumbling line indicates that there is a negative relationship between the variables. If the data is thrown all over the place, they do not share a relationship.