Comparison of noise estimates from different methods. Black: noise from high-ℓ means of noise Monte Carlo statistics. Red: noise from the high-ℓ mean of the jackknife noise map pseudo-C_ℓ spectra. Green: noise from the binned white noise Monte Carlo maps. Blue: noise from white noise covariance matrices. Error bars are relative to values from Monte Carlo simulations. We have weighted all the values with the inverse of the analysed sky fraction, , to represent the noise levels of temperature C_ℓ spectra that would result from using full sky maps.