Plot.plot({
marks: [
Plot.lineY(stocksBig3, { x: "date", y: "close", stroke: "stock_symbol", opacity:0.4 }),
Plot.lineY(stocksBig3,Plot.windowY(
{k: 30,anchor: "middle",reduce:"mean"},
{x:"date", y:"close", stroke:"stock_symbol", tip:true})
),
Plot. text(stocksBig3, Plot.selectLast({ x: "date", y:"close", text:"stock_symbol",fill:"stock_symbol"}))
],
color: { legend: true }
})