Question

*JUST NEED 3 and 4 ANSWERED THANKS*

1. Explore the data: create a scatterplot

. 1a. Type the data into a blank SPSS spreadsheet. Name variables as Distance and Snowfall respectively. Go to Graphs-Legacy Dialogs-Scatter/Dot-Simple Scatter-Define. In the window that follows, select Distance into X axis and Snowfall into Y axis. Click on OK.

1b.Double click on the scatter plot to activate it. Double click on the horizontal axis and select the Scale tab. At Auto, uncheck all boxes. At Custom, set 0 for Minimum, 110 for Maximum, 20 for Major increments, and 0 for Origin. Click on Apply. Within the same window, activate the vertical axis and set 0 for Minimum, 70 for Maximum, 20 for Major increments, and 0 for Origin.

1c. Continue to go to Options-Reference Line from Equation. A line appears from the origin with a positive slope. The Custom Equation window contains an equation. Enter a negative slope to change the line’s direction. An approximate fitting value is -0.47, but try a few different values first to see how they will alter the line’s position. Do the same to the intercept (a right value is around 58).

1d. Go to Options-X Axis Reference Line. A vertical line appears. Double click the line so that the mouse curser turns into a cross on the line. Use the cross to grab the line, and move it to line up with 0 on the horizontal axis. Similarly, create a horizontal line to line up with 0 on the vertical axis. Use Option-Title to give the graph a title. Close Chart Editor. You will come back to revise this graph later.

2. Fitting the regression line: complete the following using the above table for your calculations

2a. Calculate means of the two variables MX = MY=

2b. Write down the formula and value of the covariance between the two variables 2

2c. Calculate the two variables’ standard deviations sX = sY=

2d. Write down the formula and value of the correlation coefficient between the two variables

2e. Write down the formula and value for the best estimate of slope b and intercept a respectively

2f. Based on 2e, write out the regression equation in which distance is the independent variable and snowfall the dependent variable. Use variable names, do not use letters X and Y.

3. Run regression in SPSS using the same variables as IV and DV respectively (That is, Distance as IV and Snowfall as DV). Compare the result with your calculations. Use the more accurate parameters (that is, regression intercept and coefficient) from printout to write regression equation. Use variable names, do not use letters X and Y.

4. Go to the graph you created in 1. Activate the graph and double click on the straight line through the data points. In the Custom Equation window, fill in the best fitting intercept and slope, click on Apply. Go to Options-Text Box. Type in the regression equation in 3, and move the text box next to the regression line. Change the title to reflect the content. Close Chart Editor. Get a printout of this graph.

The table gives Distance X from the lake in miles, and Snowfall Y in inches for seven weather stations. Case X-MX Y-My (X-Mx )(Y-My) (X-Mx)? (Y-My) 2 3 4 5 6 7 Sum X 104 102 92 96 101 78 69 Y 8 10 13 16 14 21 26 NA NA 1. Explore the data: create a scatterplot. 1a. Type the data into a blank SPSS spreadsheet. Name variables as Distance and Snowfall respectively. Go to Graphs-Legacy Dialogs-Scatter/Dot-Simple Scatter-Define. In the window that follows, select Distance into X axis and Snowfall into Y axis. Click on OK. 1b.Double click on the scatter plot to activate it. Double click on the horizontal axis and select the Scale tab. At Auto, uncheck all boxes. At Custom, set 0 for Minimum, 110 for Maximum, 20 for Major increments, and 0 for Origin. Click on Apply. Within the same window, activate the vertical axis and set O for Minimum, 70 for Maximum, 20 for Major increments, and 0 for Origin. Ic. Continue to go to Options-Reference Line from Equation. A line appears from the origin with a positive slope. The Custom Equation window contains an equation. Enter a negative slope to change the line's direction. An approximate fitting value is -0.47, but try a few different values first to see how they will alter the line's position. Do the same to the intercept (a right value is around 58). 1d. Go to Options-X Axis Reference Line. A vertical line appears. Double click the line so that the mouse curser turns into a cross on the line. Use the cross to grab the line, and move it to line up with 0 on the horizontal axis. Similarly, create a horizontal line to line up with 0 on the vertical axis. Use Option-Title to give the graph a title. Close Chart Editor. You will come back to revise this graph later.

Answer 1

(3)From above table you can compare your results with results obtained by hand.

Coefficients Standardized Coefficients Beta Unstandardized Coefficients Model B Std. Error 1 (Constant) 56.330 6.188 Distance -.446 .067 a. Dependent Variable: Snowfall Sig. .000 95.0% Confidence Interval for B Lower Bound Upper Bound 40.424 72.236 -618 - 274 9.103 -6.670 -.948 .001

(4)

Regression line

Regression Line between Snowfall and Distance 30 25- Snowfall = 56.33 -0.446*Distance 20- Snowfall 15- o o 10- o o 5 60 70 80 90 100 110 Distance