Properties of Data and Variable in Statistics

All scientific data in Science:
Measurements in the Metric System

• Volume (mL or cc)
• Distance (m or km)
• Temperature (°C)
• Weight (g) 

Types of Data:

• Ratio-constant size interval between values. Commonly used. True zero. Ex: most measurements weight, volume, length, etc. 
• Interval- Constant size interval between values, arbitrary zero. Ex: temperature, time of day, date of year
• Ordinal- ordered or ranked data, no numerical difference between data. Ranking. Ex: darker versus lighter, shorter versus taller, faster versus slower
• Nominal- non-numeric qualities or artistes, names, qualitative data. Ex: colors, gender, locations.

Variables:

• Continuous- data where there are an infinite number of values between any two individual values ex: 2.7 and 2.8
• Discrete-integers (counts) ex: 35 seals, 15 subjects

Measurement Concepts:

• Accuracy-About the measuring device. Refers to how close a measurement is to the real measurement, evaluates measuring device. Ex: a scale or balance is only accurate to the nearest 0.1g
• Precision-About the researcher. Refers to how close repeated measurements are to each other. 
• Significant Digits- Implied range
• Rounding Rules- If x>5 then round up. If x<5 then do not round.