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1. week five assignment mha 610
week five assignment mha 610week five assignment mha 610Permalink: https:// /week-
five-assignment-mha-610/Week 5 – AssignmentBrain Size and IntelligenceBackground: Is
brain size a measure of intelligence? Brain size tends to vary with body size: for example,
sperm whales and elephants have brains up to five times as massive as human brains. So
across species, brain size is not a perfect measure of intelligence. And within species, the
underlying organization (complexity of connections) and molecular activity of the brain are
likely to be more directly associated with intelligence than mere size.In this assignment, we
will investigate relationships between physiological measures of the brain, and intelligence.
Download and open the Excel workbook, MHA610_Week 5_Assignment_Brain_Data.xls. The
workbook contains data on 20 youths, in rows two through 21. Eight variables (the
columns) were recorded on each individual; the column headings are given in row one. The
column headings are as follows: IQthe individual’s IQOrderthe birth order (1 =
firstborn, 2 = not firstborn)Pairmarker for genotypeSexgender, 1 = male, 2 =
femaleCCSAcorpus callosum surface area (in cm2)HChead circumference (in
cm)TOTSAtotal brain surface area (in cm2)TOTVOLtotal brain volume (in
cm3)WEIGHTbody weight (in kg) The neuroanatomical measures CCSA, TOTSA, and
TOTVOL were determined from magnetic resonance imaging (MRI) of the brains, followed
by automated image analyses of the scans. The corpus callosum is a bundle of neural fibers
beneath the cortex, connecting the left and right cerebral hemispheres of the brain; it is the
communication highway between the two hemispheres. (The more lanes to the highway,
the faster the traffic ought to flow.)The following questions can be answered in Excel,
StatDisk, or other statistics software you may have available.Examine all of the pairwise
correlations among the physiological measures CCSA, HC, TOTSA, TOTVOL, and WEIGHT.
Which two variables have the strongest correlation? Report the correlation, and plot the
scattergram for these two variables.Determine whether the physiological parameters CCSA,
HC, TOTSA, TOTVOL, and WEIGHT are significant predictors of IQ. That is, run a sequence of
univariate regressions, with IQ as the dependent variable, and the physiological parameters
as the independent variables. Report the best univariate regression with statistics and a
graph of the regression. Describe whether IQ can be accurately predicted from any of these
brain measures individually or in combination.BONUS. Power law distributions, that is,
functional relationships between two variables in which one variable is roughly a power of
the other, are often used to model physiological data. One of the oldest power laws, the
square-cube law, was introduced by Galileo in the 1600’s: empirically, the square-cube

2. law states that as a shape grows in size, its volume grows faster than its surface area. We
shall investigate the square-cube law with two variables from our dataset, CCSA and
TOTVOL. If CCSA varies with some power of TOTVOL, for example, CCSA = k * (TOTVOL) α
(k is an unknown constant here), then a simple way of estimating the exponent α is via
linear regression: take log(CCSA) as the dependent variable and log(TOTVOL) as the
independent variable; the fitted regression coefficient (slope) is an estimate of the
exponent. (Do you see why this is true?) Perform this linear regression, and report your
results. Describe whether the regression coefficient is significantly different from 2/3. (The
2/3rd power law occurs often in nature.)