Code for question 1

vega-lite-q1

{
  "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
  "width": "container",
  "height": "container",
  "data": {
    "url": "https://raw.githubusercontent.com/vda-lab/vda-lab.github.io/master/assets/station_366.json"
  },
  "transform": [
    {
      "filter": {"field": "tripduration", "lte": "5000"}
    },
    {"calculate": "hours(datum.starttime)", "as": "hour"}
  ],
  "mark": "circle",
  "encoding": {
    "x": {"field": "hour", "type": "quantitative"},
    "y": {"field": "tripduration", "type": "quantitative"},
    "color":{"field": "usertype", "type": "nominal"}
  }
}