# 1.1 Terminology Flashcards

Does a sample mean the same thing in statistics and biology?

No, for example, sample and population are not the same in statistics and in biology

What is an individual observation?

Value (numerical or not) taken by a variable observed on an individual

What is the smallest unit in data collection? What are other units?

- Individual (smallest)
- Group
- Population (largest)

What is a statistical sample of size n? What is it also called?

- n individual observations
- Also called “sample data”
- n values taken by a variable observed on n individuals

For a given variable, how many individual observations would be observed for 1 individual?

1 individual observation

For a given variable, how many individual observations would be observed for a group of n individuals? What is this called?

n individual observations (statistical sample)

For a given variable, how many individual observations would be observed for a population of N individuals? What is this called?

N individual observations (statistical population)

What is the difference between n and N?

- N>= n
- n (statistical sample)
- N (statistical population)

What are the two main types of random variables?

- Qualitative (characters)

- Quantitative (numbers: integers, fractions, or real numbers)

What is the nominal scale?

- All one can do with the observations is “name” them

- Ex: symbols (+, -, $)

What is the ordinal scale?

- There is an order to allow for observations to be ranked: alphabetical or numerical

What is the interval scale?

- In the absence of a true zero point, data can be positive or negative
- Or, are strictly positive, so that ratios make sense
- Ex: temperatures in celsius, IQ

What is a ratio scale?

- There is a true zero point and ratios do make sense

- Ex: temperatures in Kelvin

“Plant vigor, from weak to strong” is an example of what kind of scale?

Ordinal

“Temperature in celsius” is an example of what kind of scale?

Interval

”+, -, $, ?” is an example of what kind of scale?

Nominal

“Temperature in Kelvin” is an example of what kind of scale?

Ratio

What is a random variable?

Associated with the uncertainty of the outcome of an observation

List the scales of observation from the scale that you can manipulate the least to the most.

- Nominal (least)
- Ordinal
- Interval
- Ratio (most)

What are three orders used by the ordinal scale?

- Alphabetical (A is smaller than B)
- Numerical
- Grades (A is greater than B)

“Numerical codes, such as 032, 134, etc.” are an example of which kind of scale?

Ordinal scale

Which scales of observation are qualitative? Which scales are quantitative?

- Qualitative: nominal and ordinal

- Quantitative: interval and ratio

Define an individual.

Location observed on a given day at a given time

Can the length of an interval be negative?

No, it must always be positive

Statistically speaking, the number of towns visited by a candidate on a day during an election campaign (Note: Candidates may take ‘days off’, when they visit no town.) is observed at the _________ scale.

ratio