Statistics. Why?

why.lua

cookie.statistics.juxtapose = function(tbl1,tbl2)
    local t1 = {}
    local t2 = {}
    
    local t1_total = 0
    t1.count = 0
    for k,v in ipairs(tbl1) do
        t1.count = t1.count + 1
        t1_total = t1_total + tonumber(v)
    end
    t1.mean = t1_total/t1.count
    local t1_rawvar = 0
    for k,v in ipairs(tbl1) do
        t1_rawvar = t1_rawvar + (v-t1.mean)^2
    end
    t1.var = t1_rawvar/t1.count
    
    local t2_total = 0
    t2.count = 0
    for k,v in ipairs(tbl2) do
        t2.count = t2.count + 1
        t2_total = t2_total + tonumber(v)
    end
    t2.mean = t2_total/t2.count
    local t2_rawvar = 0
    for k,v in ipairs(tbl2) do
        t2_rawvar = t2_rawvar + (v-t2.mean)^2
    end
    t2.var = t2_rawvar/t2.count
    
    local out = {
        "'Anal'ysis: ",
        "Table 1: ",
        ".   Mean: "..t1.mean,
        ".   Variance: "..t1.var,
        ".   Elements: "..t1.count,
        ".   Cumulation of elements: "..t1_total,
        "Table 2: ",
        ".   Mean: "..t2.mean,
        ".   Variance: "..t2.var,
        ".   Elements: "..t2.count,
        ".   Cumulation of elements: "..t2_total,
        "Direct juxtaposition: ",
        ".   Mean: "..(t1.mean/t2.mean*100).."%",
        ".   Variance: "..(t1.var/t2.var*100).."%"
    }
    
    return table.concat(out,"\n")
end