The purpose of a study by Tam et al. (A-15) was to investigate the wheelchair maneuvering in individuals with lower-level spinal cord injury (SCI) and healthy controls. Subjects used a modified wheelchair to incorporate a rigid seat surface to facilitate the specified experimental measurements.

Interface pressure measurement was recorded by using a high-resolution pressure-sensitive mat with a spatial resolution of 4 sensors per square centimeter taped on the rigid seat support. During static sitting conditions, average pressures were recorded under the ischial tuberosities. The data for measurements of the left ischial tuberosity (in mm Hg) for the SCI and control groups are shown below.

Control 131 115 124 131 122 117 88 114 150 169 SCI 60 150 130 180 163 130 121 119 130 148 Source: Eric W. Tam, Arthur F. Mak, Wai Nga Lam, John H. Evans, and York Y.

Chow, “Pelvic Movement and Interface Pressure Distribution During Manual Wheelchair Propulsion,” Archives of Physical Medicine and Rehabilitation, 84 (2003), 1466–1472.

(a) Find the mean, median, variance, and standard deviation for the controls.

(b) Find the mean, median variance, and standard deviation for the SCI group.

(c) Construct a box-and-whisker plot for the controls.

(d) Construct a box-and-whisker plot for the SCI group.

(e) Do you believe there is a difference in pressure readings for controls and SCI subjects in this study?