9 Population vs Samples

Population

Sample

• The complete Collection of all people, score, ect.
• All Canadians
• Uses Greek letters (often)
• μ (mu), σ (sigma)
• Conduct a census
• Expensive

• A sub-collection of elements of the population
• 200 people at the mall
• Always uses English letters
• x̅, s
• Conduct a survey
• Relatively affordable

Parameter

• Describes an element of a population
• The average Canadian is μ = 170 cm
• The true proportion of left-handed people is π = 10%
• We tend to use Greek letters.

Statistic

• Describes an element of a population
• The average height in class is x̅ =168 cm
• The proportion of left-handed people in my survey database is $\hat{p}$ = 4.5%
• We tend to use English letters, often with a bar or hat.