Results from the Fisher analysis of the three different summary statistics of the 21cm signal, when three astrophysical parameter are varied, as we have noiseless data, considering cosmic variance as the only source of variance. Top: corner plot of our noiseless Fisher analysis, showing that ${\overline{\varphi }}_{{\ell }^2:1,2,3,4}^{\mathrm{WM}}$ provides the tightest contours. Bottom: the ±68% credibility intervals of our different astrophysical parameters, for each statistic. The ordering of the statistics is based on their performance, going from least constraining statistic (top) to most constraining (bottom).