ellipse

mu_eta = 155.1208;
mu_ksi = 78.15625;
p=-0.72685;
sig_eta = 7.848;
sig_ksi = 6.199;
x=mu_ksi-2*sig_ksi:0.001:mu_ksi+2*sig_ksi;
y1= mu_eta+p*(sig_eta/sig_ksi)*(x-mu_ksi)+(sig_eta/sig_ksi)*sqrt(1-p*p)*...
    sqrt(4*sig_ksi.^2-(x-mu_ksi).^2);
y2= mu_eta+p*(sig_eta/sig_ksi)*(x-mu_ksi)-(sig_eta/sig_ksi)*sqrt(1-p*p)*...
    sqrt(4*sig_ksi.^2-(x-mu_ksi).^2);
plot(x,y1)
hold on
plot(x,y2)