# 1.2 Graphical Representation of Sample Data Flashcards

1
Q

What are the two main types of plots?

A
• Data plots

- Frequency plots

2
Q

What are examples of data plots?

A
• Line chart (in time)
• 2D plots (in space)
• Biplot
• Scattergram
3
Q

What are examples of frequency plots?

A
• Pie chart
• Bar chart
• Histogram
• Frequency polygon
• Frequency table
4
Q

What is a discrete quantitative random variable?

A

When the number of its possible values is 1) infinite or 2) infinite and COUNTABLE (integers or fractions)

5
Q

What is a continuous quantitative random variable?

A

When the number of its possible values is infinite and UNCOUNTABLE (real numbers)

6
Q

What is the notation for random variables?

A

Capitals

7
Q

What is the notation for observed values of random variables?

A

Small letters

8
Q

What is a real number?

A

A real number includes irrational numbers (cannot be constructed from ratios)

9
Q

Is this an example of a discrete or continuous quantitative random variable:
Counting the number of eggs a chicken lays.

A

Discrete quantitative random variable

10
Q

Is this an example of a discrete or continuous quantitative random variable:
Counting the number of bacteria in a swamp.

A

Continuous quantitative random variable

11
Q

Is this an example of a discrete or continuous quantitative random variable:
Weight, height, nitrogen content, speed of a car, cholesterol rate in blood

A

Continuous quantitative random variable

12
Q

For a given random variable X, how would you illustrate the random sample of size n?

A

Xn

13
Q

For a given random variable X, how would you illustrate the individual observation?

A

xn

14
Q

What directs the drawing of frequency plots?

A

The nature of a random variable (qualitative, discrete quantitative, continuous quantitative)

15
Q

What can be added up to n? What is n?

A
• Frequencies or counts

- n is the sample size

16
Q

What do relative frequencies add up to?

A

1.0 or 100%

17
Q

What is a random variable?

A
• Characteristic whose value varies among the individuals of a biological population
• Cannot be predetermined
18
Q

Which main type of graphical representation requires at least two variables?

A

Frequency plots** verify with prof

19
Q

What kind of plot would you use to collect observations sequentially in time?

A

Line chart (data plot)

20
Q

What are two-dimensional (2D) plots used for?

A

To illustrated spacial data occurring along two axes

21
Q

Give an example of discrete quantitative data in a 2D plot.

A

Abundance in a quadrant (e.g. trees)

22
Q

Give an example of continuous quantitative data in a 2D plot.

A

Soil pH

23
Q

What is a biplot or scattergram?

A

Individual observations for one random variable X are plotted against the observations on the SAME individuals for another random variable Y

24
Q

What is the restriction of a scattergram?

A
• They are restricted in that each pair of observations is collected on the same individual
• They are NOT restricted to spatial data
25
Q

How is relative frequency obtained?

A

By dividing the frequency by the sample size (n)

26
Q

Are grades (100% scale) discrete or continuous quantitative?

A

Continuous quantitative, because we ASSUME that any mark between 0 and 100 is possible

27
Q

What kind of data can a pie chart be used for?

A
• Qualitative
• Discrete quantitative
• Continuous quantitative
28
Q

What kind of data can a bar chart be used for?

A
• Qualitative
• Discrete quantitative
• NOT for continuous quantitative
29
Q

What kind of data can a histogram be used for?

A

Restricted to continuous quantitative random variables

30
Q

What is a frequency polygon?

A

Successive histogram ordinates are connected at class midpoints