Figure 3.

Strength of the primary tones necessary to produce a 2f₁−f₂ DPOAE of constant magnitude in those sheep that did exhibit DPOAEs. Approximately one-third of the sheep having CEOAEs did not have measurable DPOAEs. The primary tones always were of equal level. Large ordinate values here correspond to weak DPOAEs. For both sexes, the control groups consisted of the untreated∕intact animals (males were untreated∕VX) plus the untreated∕GDX animals. Error flags designate standard errors of the mean.