math

• What does the large data set contain data for?

  Different variables at each weather station
• How is daily mean temperature calculated?

  Average of hourly temperature readings over 24 hours
• What is included in daily total rainfall measurements?

  Rainfall and melted solid precipitation
• How are amounts of rainfall less than 0.05 mm recorded?

  Recorded as 'tr' or 'trace'
• How is daily total sunshine recorded?

  To the nearest tenth of an hour
• What does daily mean wind direction represent?

  Averaged over 24 hours from midnight to midnight
• How is mean wind direction expressed?

  As bearings and cardinal directions
• How is mean windspeed categorized?

  According to the Beaufort scale
• What is the Beaufort scale used for?

  • Describing wind speed
  • Categorizing wind conditions
• What is the notation for a knot (kn)?

  A nautical mile per hour
• What is the average speed for a Beaufort scale term 'Calm'?

  Less than 1 knot
• What is the average speed for a Beaufort scale term 'Light'?

  1 to 10 knots
• What is the average speed for a Beaufort scale term 'Moderate'?

  11 to 16 knots
• What is the average speed for a Beaufort scale term 'Fresh'?

  17 to 21 knots
• What additional information is recorded with daily maximum gust?

  The direction from which the maximum gust was blowing
• What is recorded as daily maximum gust?

  Highest instantaneous windspeed recorded
• What does daily maximum relative humidity represent?

  Percentage of air saturation with water vapour
• What conditions arise from relative humidities above 95%?

  Misty and foggy conditions
• What data is recorded for overseas locations?

  • Daily mean temperature
  • Daily total rainfall
  • Daily mean pressure
  • Daily mean windspeed
• What is the difference between stratified sampling and simple random sampling?

  • Stratified sampling divides population into strata
  • Simple random sampling selects individuals randomly
• What is the first step in stratified sampling?

  Population divided into mutually exclusive strata
• What is the purpose of using a list/register in stratified sampling?

  To take a random sample from each stratum