how to plot maximum and minimum point from excel column?

I want to plot values of one column from excel file and mark all the minimum points in red * and maximum in green * this is what I got so far:

colA = xlsread('MinMaxVal.xlsx','B:B');
colB = xlsread('MinMaxVal.xlsx','B:B'); 
plot(colA);                           
hold on;

I defined colB to use it for marking the points.

tnx

Answer 1

[KSSV]

k = rand(100,1) ;  %  a random data, in your case your column read from excel 
plot(k) ;
hold on
% plot maximum
[val,id] = max(k) ;
plot(id,k(id),'*g')
% plot minimum
[val,id] = min(k) ;
plot(id,k(id),'*r')

[Tsvi Weiss]

tnx i tried it and it show me only one min and one max points how can i find the entire local min and max points of the values and plot them on the same line? picture added of the all the points marked in green *the excel table has 2 columns (A: date B:value of the date) and 96 rows of values of each date (2 to 97)

[KSSV]

k = rand(100,1) ;  %  a random data, in your case your column read from excel 
plot(k) ;
hold on
mu = mean(k) ;
idx = 1:length(k) ;
% plot all maximums
plot(idx(k>mu),k(k>mu),'*g')
% plot minimum
plot(idx(k<mu),k(k<mu),'*r')