Why there's opposite fit results phenomenon between the oddnomial and the evennmnial?

p=polyfit(RANKING,Total,4);
y=polyval(p,Total);
plot(y)

Answer 1

[Mathieu NOE]

hello

I suspect this is what you wanted to do (?)

load('Ranking.mat')
plot(RANKING,Total);grid on
hold on 
order = 5; % 3 and above are fine 
p=polyfit(RANKING,Total,order);
% y=polyval(p,Total);
y=polyval(p,RANKING);
plot(RANKING,y)
legend('data','fit');
hold off

[Zhssss]

Thank you bro,that's just what I want.

[Mathieu NOE]

as always, my pleasure !