How to deal with this grpstat error message

I have an error message

https://imgur.com/a/OGCDL4n

Please advise the next step.

Answer 1

[the cyclist]

I think you want to use "mean" instead of "average" for the summary statistic.

[alpedhuez]

Thank you.

Answer 2

[Image Analyst]

You need to have braces around the average and sum, not brackets

{"average", "sum"}

[the cyclist]

String arrays are actually allowed there.

load patients
tbl = table(Gender,Age,Weight,Smoker);
tblstats = grpstats(tbl,["Gender","Smoker"],["mean","sum"],"DataVars","Weight")

tblstats = 4×5 table
                  Gender      Smoker    GroupCount    mean_Weight    sum_Weight
                __________    ______    __________    ___________    __________

    Male_0      {'Male'  }    false         26          180.04          4681   
    Male_1      {'Male'  }    true          21          181.14          3804   
    Female_0    {'Female'}    false         40          130.32          5213   
    Female_1    {'Female'}    true          13          130.92          1702   

[alpedhuez]

https://www.mathworks.com/help/stats/grpstats.html

has

tblstats3 = grpstats(tbl,["Gender","Smoker"],["min","max"], ...
    "DataVars","Weight")

[the cyclist]

It's easy to get muddled, because if you specify the input arguments as character arrays rather than strings, then you do need to use curly braces. (Notice the single quotes rather than the double quotes around the arguments.)

load patients
tbl = table(Gender,Age,Weight,Smoker);
tblstats = grpstats(tbl,{'Gender','Smoker'},{'mean','sum'},'DataVars','Weight')

tblstats = 4×5 table
                  Gender      Smoker    GroupCount    mean_Weight    sum_Weight
                __________    ______    __________    ___________    __________

    Male_0      {'Male'  }    false         26          180.04          4681   
    Male_1      {'Male'  }    true          21          181.14          3804   
    Female_0    {'Female'}    false         40          130.32          5213   
    Female_1    {'Female'}    true          13          130.92          1702   

[alpedhuez]

Thank you. "You specify the input arguments as character arrays rather than strings". Will you explain a bit more?