Question

the following table shows student test scores on the first two tests in into three chemistry class. If a student scored a 74 on his first test, make a prediction for his score on the second test . Assume the regression equation is appropriate for prediction. Round your answer to two decimal places if necessary

Answer 1

Regression equation

68.29

Step-by-step explanation

If we locate each point (x, y) on the plane we will obtain the following graph:

We can approximate the resulting figure to a straight line:

In order to discover the equation of this line we use a linear regression calculator and enter the values as follows:

The calculator gives as the following equation as an approximation:

ŷ = 0.82X + 7.61

Using this equation we can predict the score of the second test of the exam using the score of the first test.

On this case, we want to make a prediction for a score on the second test if a student scored a 74 on his first test.

This means, we want to find ŷ when X=74. Let's replace it on the equation:

`\begin{gathered} ŷ=0.82X+7.61 \\ \downarrow \\ ŷ=0.82\cdot74+7.61 \\ ŷ=68.29 \end{gathered}`

That is why we can say that the student will have 68.29 as his score on the second test.