Statistical Principles

Question 1

Reflects the ability of a data-gathering instrument or tool, such as a survey or a rater’s observation or physical measurement, to provide results that are consistent.

Answer 1

Reliability

Question 2

The ability of an instrument to measure what it is intended to measure. It answers to questions: What does the instrument measure and How well does the instrument measure it?

Answer 2

Validity

Question 3

Often used when the population to be analyzed is very large or when data cannot be obtained from the entire population.

Answer 3

Sampling

Question 4

It can occur in a controlled study when participants are not randomly assigned to control and experimental groups. It can also occur when researchers choose to enroll only certain types of participants.

Answer 4

Selection

Question 5

This is the inverse of selection bias. The researchers invite a representative sample to join a study, but the group that accepts or responds is not representative.

Answer 5

Response

Question 6

Participants in a controlled study behave differently because they are being studied.

Answer 6

Performance

Question 7

Raters are measuring incorrectly, either unintentionally or intentionally.

Answer 7

Measurement

Question 8

Identifies the degree of difference between planned and actual performance. Usually applied to analysis against objective baselines, such as schedules and budgets.

Answer 8

Variance analysis

Question 9

Compares the relative size of two variables and yields a percentage.

Answer 9

Ratio analysis

Question 10

Examines data from different points in time to determine if a variance is an isolated event or if it is a part of a longer trend.

Answer 10

Trend analysis

Question 11

Refers to a statistical method used to determine whether a relationship exists between variables and the strength of the relationship.

Answer 11

Regression analysis

Question 12

Starts with a result and then works backwards.

Answer 12

Root-cause analysis

Question 13

Used to test the possible effects of altering the details of a situation to see how the outcomes will vary under different conditions.

Answer 13

Scenario/what-if analysis

Question 14

Often used to support these types of analysis and to visualize results.

Answer 14

Graphic data analysis

Question 15

Graphically depicts as portions or slices of a circle the constituents that comprise 100% of a data group.

Answer 15

Pie Chart

Question 16

Graphically depicts the sorting of data into groups arranged in the shape of a statistical distribution, showing a central tendency and dispersion around that tendency.

Answer 16

Histogram

Question 17

Plots data points on two axes. The horizontal axis usually represents time, while the vertical axis represents volume.

Answer 17

Trend Diagram

Question 18

Applies the Pareto principle (that 80% of effects come from 20% of causes) in the form of a histogram.

Answer 18

Pareto Chart

Question 19

Plots data points against two variables that form the chart’s x and y axes. Each axis is scaled. The pattern formed by the plotted data describes the correlation between the two variables.

Answer 19

Scatter Diagram