Model Trendline Linear 2Y1X Excel 2013 V0D 1 by Milo Schield Member: International Statistical Institute US Rep: International Statistical Literacy Project Director, W. M. Keck Statistical Literacy Project Slides at: /Model-Trendline-Linear-2Y1X-Excel2013-6up.pdf Model using Trendline Linear 2Y1X in Excel 2013

Model Trendline Linear 2Y1X Excel 2013 V0D 2 Background The pulse.xls dataset contains data on college students. After recording rest pulse, height, weight, etc., student flipped coins. One group (Run=1) jogged in place for a minute; the other group watched. Afterward, everyone recorded their pulse a second time (Pulse2). Thus, the meaning of Pulse2 depends on the value of RUN. To separate the two groups, sort on RUN and select just those rows that have the desired value of RUN. Goal: Create four graphs shown on slides 13, 24, 29 and 34. N1 Run=1 rows; N2 All rows; N3 Run=0 rows; N4 Run=1 rows.

Model Trendline Linear 2Y1X Excel 2013 V0D 3 Goal: Summarize association for two series of variables A. Generate an XY chart showing association between two quantitative variables having a common X. Generate four graphs on slides 13, 24, 29 and 34. B. Show trend-line for each series. C. Show linear regression equation for each series. D. Show R 2 for each series. Use XL1 (Pulse.xls) data set. For details on using Excel Chart Trendline to build a model, see Model-Trendline-Linear-Excel2013-6up.pdf

Model Trendline Linear 2Y1X Excel 2013 V0D 4 1) Pulse1 and Pulse2 vs. Ht. Select all data prior to Sort.

Model Trendline Linear 2Y1X Excel 2013 V0D 5 1) Sort on Run: Descending.

Model Trendline Linear 2Y1X Excel 2013 V0D 6 1) Results of Sort on Run.

Model Trendline Linear 2Y1X Excel 2013 V0D 7 1) Select Pulse1 for Run = 1. (Rows 2-36). Insert XY Plot. Rows 2-36

Model Trendline Linear 2Y1X Excel 2013 V0D 8 1) Select Pulse1 series Right-mouse. “Select Data”.

Model Trendline Linear 2Y1X Excel 2013 V0D 9 1) To insert X values, select Edit.

Model Trendline Linear 2Y1X Excel 2013 V0D 10 1) Either select X values range or copy Y, paste to X and edit Pulse1 is Y axis (A2:A36); Height is X axis (C2:C36)

Model Trendline Linear 2Y1X Excel 2013 V0D 11 1) To add a 2 nd series (Pulse2 by Height), select “Add”

Model Trendline Linear 2Y1X Excel 2013 V0D 12 1) Add Pulse2 (B2:B36) as Y; Add Height (C2:C36) as X Press OK

Model Trendline Linear 2Y1X Excel 2013 V0D 13 1) Result: Two Series same Y axis Format axis; add trendlines

Model Trendline Linear 2Y1X Excel 2013 V0D 14 1) Two Y sharing same axis: Describe results in words Slope: As height increases by 1”, rest pulse decreases by 1 bpm. As height increases by 1”, active pulse decreases by 3 bpm. R-squared 29% of the variation in active pulse is explained by height. 10% of the variation in rest pulse is explained by height. Difference between Trendlines Active pulse is 10 to 40 bpm higher than rest pulse. Predict your rest pulse using your height. ____ Record your height and your rest pulse: _______, _________

Model Trendline Linear 2Y1X Excel 2013 V0D 15 2) Right mouse N1 Tab; Copy N1 Rename as N2; Delete graph. Use new worksheet. Otherwise new sort will change previous graphs.

Model Trendline Linear 2Y1X Excel 2013 V0D 16 2) Select all Pulse1 (A2:A93) Insert XY chart.

Model Trendline Linear 2Y1X Excel 2013 V0D 17 2) Initial Chart: 1Y, no X.

Model Trendline Linear 2Y1X Excel 2013 V0D 18 2) Right-mouse on Data; Select “Select Data”.

Model Trendline Linear 2Y1X Excel 2013 V0D 19 2) Edit Pulse1 by Height series: X (C2:C93), Y (A2:A93).

Model Trendline Linear 2Y1X Excel 2013 V0D 20 2) Add Weight by Height series.

Model Trendline Linear 2Y1X Excel 2013 V0D 21 2) Edit Weight by Height Series X (C2:C93), Y (D2:D93)

Model Trendline Linear 2Y1X Excel 2013 V0D 22 2) To Introduce Second Y Axis: Right-mouse Weight; Select “Change Type”

Model Trendline Linear 2Y1X Excel 2013 V0D Add check to check box for Secondary Axis for “Weight”. Do not press “Combo”; Do not select a particular chart shape. 23 2) Check Secondary Y Axis for Weight. Press OK

Model Trendline Linear 2Y1X Excel 2013 V0D 24 2) Two Series; Separate Y Axis. Add Trendline w Model for each. Left-Y-axis: Max=180. Right-Y-axis: Min = -125; Max=225

Model Trendline Linear 2Y1X Excel 2013 V0D 25 3)Right Mouse N2 tab; Copy N2; Rename as N3; Delete graph Use new worksheet. Otherwise new sort will change previous graphs.

Model Trendline Linear 2Y1X Excel 2013 V0D 26 3)Select all columns/all rows; From Home or Data tab, select Sort

Model Trendline Linear 2Y1X Excel 2013 V0D 27 3)From Sort-by, select RUN; Order from Small-to-Large

Model Trendline Linear 2Y1X Excel 2013 V0D 28 3)Select Pulse1 and Pulse2; Select Run=0 only (Rows 2-58)

Model Trendline Linear 2Y1X Excel 2013 V0D 29 3) Pulse2 after vs Pulse1 before Add “No Change” line: 45,45 – 95,94 Excel: Insert/ Shapes OR Chart Tools/Format/Insert Shapes PowerPoint: Insert/Shapes. Manually place line corner-to-corner To create a diagonal line:

Model Trendline Linear 2Y1X Excel 2013 V0D 30 4) Right-Mouse N3 Tab; Copy N3 Rename as N4. Delete graph Use new worksheet. Otherwise new sort will change previous graphs.

Model Trendline Linear 2Y1X Excel 2013 V0D 31 4) Select all data; Sort by Run; Sort Values: Large to Small

Model Trendline Linear 2Y1X Excel 2013 V0D 32 4) Select Pulse1 & 2 for Run=1 Rows 2:36. Insert XY Chart

Model Trendline Linear 2Y1X Excel 2013 V0D 33 4) Add Trendline & Model* Insert no-change line: 55,55-105,105 * Format Axis; Add headings

Model Trendline Linear 2Y1X Excel 2013 V0D 34 4) Modify Intercept so Slope=1 Set Intercept = Note: This slide is slightly different from the previous slide.

Model Trendline Linear 2Y1X Excel 2013 V0D 35 Summary of N3 and N4 N3: Test-retest of rest pulse has a correlation of 0.92: Sqrt(R-squared) = Sqrt(0.8521). Thus, 15% of the variability in the retest of Pulse1 involves other factors than the prior test. N4: Run in place increases rest pulse by an average of 18.9 bpm when model has unit slope. Rest pulse explains 37% of active pulse variability

Model Trendline Linear 2Y1X Excel 2013 V0D 36 Two Common Problems 1.Including column heading in data selection. You may include top row when you select data. Normally Excel excludes this so the data starts in row 2. Sometimes Excel does not exclude row 1 and this really messes up your graph! 2.Getting X (horizontal axis) and Y (vertical axis) reversed. There is no simple way to fix this. You need to right mouse the data, select “select data” and Edit the data in question. Manually make the changes necessary without making things worse…