Group and individual means

I have a dataset of kinematic angular values. Each row representing 100 datapoints of angular data (Y). I have a column vector containing my subject numbers (1-9) and another column vector indicating three different conditions (A).

I am able to calculate the group mean for each

YS1 = Y(Sub==1)

SubMean = mean (Y1S)

(All conditions, 1 subject)

Same for condition mean

YA1 = Y(A==1)

SubMean = mean (YA1)

(All subjects, 1 condition)

How can I combine it to to get the mean for 1 subject AND 1 condition - Thus (Sub==1) AND (A==1)

Answer 1

[per isakson]

Try this

YSA1 = Y(Sub==1&A==1);
SubMean = mean (YSA1);

[Liz Mat]

Thanks for the quick response

This is the error I get:

YSA1 = Y(SUBJ==1,: & A==32,:);

↑

Error: Invalid use of operator.

When I try:

YSA1 = Y(SUBJ==1,:) && Y(A==32,:);

I get the error:

Operands to the || and && operators must be convertible to logical scalar values.

My variables are:

SUBJ = 135x1

A = 135x1

Y = 135x101

[per isakson]

Replace

YSA1 = Y(SUBJ==1,: & A==32,:);

by

YSA1 = Y( SUBJ==1 & A==32 );

i.e. remove the commas and the colons. See my answer

[Liz Mat]

Thank you!

Answer 2

[Liz Mat]

I managed to get it working:

SA1 = (Sub==1)&(A==1);

YSA1 = Y(SA1,:);

SubMean = mean (YSA1);

It might be bit lengthy though.

[per isakson]

The parentheses in SA1 = (Sub==1)&(A==1); are not needed.