We will use the StatDisk. Go towww.statdisk.comand open a fresh spreadsheet.

For scatter plots, enter Age in Column 1 and Vocabulary in Column 2 and generate a scatter plot. Go to the Data drop-down menu and select "Scatter Plot." The x-value should be the explanatory variable and y-value should be the response variable.

Be sure to label the x and y axis, and then generate a scatter plot and cut and paste it into this document. Use the StatDisk scatterplot displayed to answer the following questions.

Use the following data set to answer the questions about correlation.

The table shows the Age and Vocabulary Size. Researchers examined data from 11 different children between the ages of 1 and 6.

Age 1 2 3 4 5 6 3 5 2 4 6 Vocab 3 440 1200 1500 2100 2600 1100 2000 500 1525 2500 Size

1.

Answer this preliminary question before you start:Do you think that there is a relationship between age and vocabulary size?

2.

Scatter Plots

a. Who are the individuals in this study? b. What is the explanatory variable? c. What is the response variable? d. Make a scatter plot where the x-axis shows the explanatory variable, and the y-axis

shows the response variable. e. Describe the form, direction, and strength of the relationship?

For correlation, click on the Analysis drop down and select "Correlation and Regression." Leave the significance level at 0.05, and keep the x and y value the same as above. Ther, a, b, and r squaredvalues all listed on the output. Cut and paste the entire output into the document and answer the following questions.

Correlation measures thestrengthanddirection (type)of linear relationships and is quantified by using the correlation coefficient (r-value).

r = _________________

Using the information from the output you can write the equation for the regression in they = a + bxform. Statdisk calls the values by a different name, but they follow the same pattern. See the "Regression Results" on the output for the info and translate them into our notation before writing the equation for the "least squares line."

a = _________ b= _________

Thesquare of the correlation,r2, is the proportion of the variation in the values of y that is explained by the linear relationship with x.

r2= ________

3. Correlation and regression

Find the correlation coefficient for this relationship.

What proportion of variation can be explained by the linear relationship between the

two variables?

Write the linear equation for the least squares line for this relationship?

Use the equation to predict the age of a child with a vocabulary size of 2,200.

Use the equation to predict the vocabulary size the corresponds to an eight-year-old

child.

Why or why not should you use this model predict the vocabulary size of an eight-year-

old child?

Final analysis:Do you think that there is a relationship between age and vocabulary size?

4.Revisit/re-evaluate the question from the beginning. Do you have any new evidence suggesting this to be true or false? Explain.