Hold on command does not work for boxplot and additional plot

Hello all,

I've got a boxplot (with horizontal orientation) with data:

a=  [x1;x2;x3;x4;x5;x6;x7;x8;x9;x10;x11;x12;x13;x14;x15]

and the boxplot groups are defined by vector b, where b is:

 b = [0*ones(size(x1)); 0.1*ones(size(x2)); 0.2*ones(size(x3)); 0.3*ones(size(x4)); 0.4*ones(size(x5)); 0.5*ones(size(x6)); 0.6*ones(size(x7)); 0.7*ones(size(x8)); 0.8*ones(size(x9)); 0.9*ones(size(x10)); 1.0*ones(size(x11)); 1.1*ones(size(x12)); 1.2*ones(size(x13)); 1.5*ones(size(x14)); 1.6*ones(size(x15))];

where, the positions 0, 0.1, 0.2, 0.3, 0.4......., 1.6 are the positions that my horizontal boxplots are taking on the y axis.

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I want to overlap a plot with 5 points say c=[0.3, 0.4, 0.5, 0.6, 0.7] at y=2.

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So, when I'm typing

figure

boxplot(a,b,'orientation','horizontal')

hold on

plot(c,2*ones(size(c)),'g.')

it does not work and only the boxplots are shown, but not my 5 points (that are above the highest y value of the boxplots, which is 1.6).

Any ideas of how I could resolve this?

Answer 1

[Walter Roberson]

"hold on" affects the xlim and ylim.

[Christina]

But still when I added the command

axis([xlim 0 3])

, then the limits of the y axis were from -0.1 to slightly above 0.1

[Walter Roberson]

I do not have the Stats toolbox so I cannot test this.

You are passing in your b in G, the grouping variables. Grouping variables designate only groupings, not positions. And I think you are passing in the wrong size of grouping variables unless your x* values are all column vectors.

I think what you are wanting is the 'positions' option:

Box positions specified as a numeric vector with one entry per group or X value. The default is 1:numGroups, where numGroups is the number of groups.

Your grouping variable might as well be integer valued,

[1 * ones(size(x1,1),1); 2 * ones(size(x2,1),1); ... ]

and then your 'positions' would be 0:.1:1.6

and then you would be able to meaningfully plot at y=2 and not have it show up near the bottom of your plot.

I suggest, by the way, that instead of using

hold on

that you use line() to draw the line instead of using plot() to draw it. line() is a graphics primitive object that does not erase anything.

[Christina]

Hi Walter,

Thank you for your reply.

I think I resolved the first part with plotting boxplots correctly.

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So, when I've got

Xpos = [0 0.1 0.2] (just for three boxplots and not for 15)

group = [repmat(Xpos(1),[size(x1),1]); repmat(Xpos(2),[size(x2)],1); repmat(Xpos(3),[size(x3)],1)]

dataset3 = [x1;x2;x3];

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figure

boxplot(dataset3, group,'positions', Xpos,'orientation','horizontal')

hold on

scatter(0.5,2,'g.') (just for one additional point and not for 5 that I want)

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my point is still not visible.

I do understand that hold on is restraining the ylimits, but what can I use instead?

Many thanks