Frequency Distribution Histogram

Histogram of Brain Volumes-Model Problem/Tutorial

Brain Volume Data1

1005, 963,1035,1027,1281,1272,1057,1079,1034,1070,1173,1079,1067,1104,1347,1439,1029,1100,1204,1160

Preliminaries

1. Identify W’s, (WHO, WHAT, WHEN,…, hoW )

Graphical Analysis

1. Identify shape of this histogram and explain its meaning in terms of diatributed variable.

2. Estimate/Identify center of distribution, its lower-end, and its upper-end.

3. Are there outliers?

Selected Descriptive Statistics

1. Determine measures of center of this distribution: sample mean, sample median, sample mode, sample midrange.

2. Determine measures of spread: range, sample variance, sample standard deviation, sample interquartile range.

3. Determine five-number summary of these data.

4. Answer the following:

a. Estimate how many brain volumes are less 1100 cu.cm.

b. Estimate how many brain volumes are more than 1300 cu.cm.

c. Estimate how many brain volumes are less 1300 cu.cm but more than 1000 cu.cm.

Extensions:

1. Construct relative frequency distribution histogram of Brain Volumes variable.

2. Answer the following:

a. Estimate what percent of brain volumes are less 1100 cu.cm.

b. Estimate what percent of brain volumes are more than 1300 cu.cm.

c. Estimate how many brain volumes are less 1300 cu.cm but more than 1000 cu.cm.

  1. Data Set 6: Extracted from M.F Triola, Essential s of Statistics Fifth Edition, Pearson. Originally provided by M.J. Tramo,W.C. Loftus, T.A. Stukel, J. B. Weaver, M.S. Gazzinga. See “Brain Size, Head Size, and IQ in Monozygotic Twins”, Neurology, Vol. 50.↩