data = data_middlebrooks1999
data_middlebrooks1999 returns statistics summary from Fig. 13 (Middlebrooks, 1999b) showing the effect of non-individualized HRTFs.
Statistics of those parameters are stored as .mean and .quantiles representing the arithmetic mean and {0,5,25,50,75,95,100} quantiles, respectively.
J. C. Middlebrooks. Virtual localization improved by scaling nonindividualized external-ear transfer functions in frequency. jasa, 106:1493-1510, 1999.