PAIR SEX ORDER IQ VOL AREA CCSA CIRC WT 1 2 1 96 1005 191388

PAIR	SEX	ORDER	IQ	VOL	AREA	CCSA	CIRC	WT
1	2	1	96	1005	1913.88	6.08	54.7	57.607
1	2	2	89	963	1684.89	5.73	54.2	58.968
2	2	1	87	1035	1902.36	6.22	53	64.184
2	2	2	87	1027	1860.24	5.8	52.9	58.514
3	2	1	101	1281	2264.25	7.99	57.8	63.958
3	2	2	103	1272	2216.4	8.42	56.9	61.69
4	2	1	103	1051	1866.99	7.44	56.6	133.358
4	2	2	96	1079	1850.64	6.84	55.3	107.503
5	2	1	127	1034	1743.04	6.48	53.1	62.143
5	2	2	126	1070	1709.3	6.43	54.8	83.009
6	1	2	101	1173	1689.6	7.99	57.2	61.236
6	1	1	96	1079	1806.31	8.76	57.2	61.236
7	1	2	93	1067	2136.37	6.32	57.2	83.916
7	1	1	88	1104	2018.92	6.32	57.2	79.38
8	1	2	94	1347	1966.81	7.6	55.8	97.524
8	1	1	85	1439	2154.67	7.62	57.2	99.792
9	1	1	97	1029	1767.56	6.03	57.2	81.648
9	1	2	114	1100	1827.92	6.59	56.5	88.452
10	1	2	113	1204	1773.83	7.52	59.2	79.38
10	1	1	124	1160	1971.63	7.67	58.5	72.576

10-13 Statdisk Data Set: Predicting lQ Score Refer to Appendix B in the Triola textbook for data set 6 IQ and Brain Size and find the best regression equation with IQ score as the response variable. Use predictor variables of brain volume and/or weight. Why is this equation best? Based on these results, can we predict someone\'s IQ score if we know the volume and weight of their brain? Based on these results, does it appear that people with larger brains have higher IQ scores?

Solution

Enter the given data in the Excel sheet. To obtain regression relation between IQ and volume, draw a scatter plot for these columns where IQ is set on Y –axis and the Vol is set on X-axis. After drawing chart, right click on it and choose add trendline. From there select regression type linear and Display equation on chart.

Similiarly, follow the steps and now set IQ on Y –axis and WT on X-axis to obtain the regression equation between IQ and weight. This will generate the below output.

Thus the regression equation to predict IQ from volume is,   y = 0.736 x + 93.26.

And the regression equation to predict IQ from weight is,   y = - 0.001 x + 101.1.

Thus based on this result, we can predict the IQ from volume and weight by substituting the value of volume and weight in place of x respectively in the above obtained equations.

Now as can be seen from the equations that the slope of the first equation is positive therefore the IQ will be higher for larger volume however the slope of the second equation is negative therefore the IQ will be lower for large weight of

brain.