In the code you shared, I see 3 inputs and one name-value pair.
vartestn(Table.trialNum, Table.Sex, Table.ID, 'TestType', 'LeveneQuadratic');
The syntax described in the documentation describes a max of 2 inputs followed by name-value pairs.
Furthermore, from the documentation, x can be specified as a matrix or column vector. If a grouping variable group is specified, then x must be a column vector. So, you have 1 too many inputs.
Decide which variable is your grouping variable and which variable contains the data you're testing.
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