The given statement is False since higher the octane number lower is the possibility of detonation. This is because octane number of a fuel is the percentage of iso-octane in the Primary Reference Fuel that gives the same knock intensity as that of the fuel.
Primary Reference Fuels are a series of reference fuels consisting of mixtures of iso-octane and n-heptane: in which iso-octane has very slight tendency to knock and is assigned 100 octane number, and n-heptane detonates rapidly and therefore is assigned an octane number of zero.
Knocking is also called detonation or abnormal combustion. Hence a fuel having less knocking tendency will have lower possibility of detonation.
So higher the octane number, higher is percentage of iso-octane and so lesser is the tendency of knocking or detonation.