The assumption behind this standard was that operators prefer to type with horizontal
underarms and 90˚ elbow angles. If so, the available vertical space between the
hands and upper legs can be calculated from anthropometric measures in Table 8.3,
such as sitting elbow height minus thigh clearance. For a small 5th percentile female
operator this is 7.5 cm, barely enough to fit a 3-cm keyboard and a 3-cm table top.
There will definitely not be space for a keyboard tray under the table top