Post Midterm 2

Question 1

What is the role/definition of statistics?

Answer 1

The collection, classification, analysis and interpretation of numerical data. It gives order and regularity.

Question 2

Primary vs. Secondary data sources

Answer 2

primary = directly from original source, (measure "in the field")
secondary = acquired from remote locations, needs to be verified with primary data

Question 3

What are the levels of measurement? What dispersion measures can be measured at each level?

Answer 3

Nominal- nothing
Order- Range, quartile range
Interval - Range, Quartile range, standard deviation
Ratio- Range, Quartile Range, standard deviation, CV

Question 4

Precision and False Precision. Name a rule.

Answer 4

Just because many decimals can be included doesn’t mean you should. When the decimal is exactly 0.5, round to the nearest even digit.

Question 5

Sample vs. Population

Answer 5

population = total set of individuals/observations in a defined group
sample= subset of individuals/ observations in a population

Question 6

Spatially explicit vs. spatially implicit

Answer 6

location is measured/ analyzed directly vs. location is not measured/analyzed directly

Question 7

Define Central Tendency. What are the 3 levels of measurement?

Answer 7

Central tendency = the number that represents the center/typical value in a frequency distribution
mode, median, mean

Question 8

define mode. what data level can it be measured at?

Answer 8

mode = the number that occurs most often (all levels)

Question 9

Define median. what data level can it be measured at?

Answer 9

median = the middle value in a set of ranked values (measured at all levels except nominal)

Question 10

Define mean. what data level can it be measured at?

Answer 10

It is the sum of the values divided by the number of observations. Interval and Ratio level only.

Question 11

Define dispersion. what are the four levels of measurement?

Answer 11

The spread or variability in a data set.

range, quartile range, standard deviation/variance, Coefficient of variation (CV)

Question 12

Define range and quartile range. what data level can they be measured at?

Answer 12

range = simplest, influenced by outliers,
- measured at ordinal, interval and ratio level
quartile range = the difference between the 25th and 75th percentile
- measured at ordinal, interval and ratio

Question 13

Define standard deviation and variance. what data level can it be measured at?

Answer 13

Both are absolute measure (Has units). It is the amount of deviation from the average.
measured at interval or ratio level.

Question 14

Define coefficient of variation. what data level can it be measured at?

Answer 14

Has no units. Related to the relative measure of dispersion. Measured by standard deviation divided by the mean.
Measured at Ratio level only.