Statistics: Summarizing Measured Data
See Jain, Chapter 12
What Is Statistics?
- You wish to learn about a universal population.
- You observe a sample of the universal population.
- Statistics is a collection of techniques to make inferences
about the universal population from the sample.
Question: What is the mean time required to complete HW1 in
CS5014 this semester?
Answer: Pick 10 students (the sample). Record their
completion times. Compute the sample mean, which is an
estimate of the mean for the entire population (all CS5014
A statistic is a number that summarizes data. Jain asks [p. 177] ...
- How can the data be reduced to a single number?
- How should you report variability of the data?
- Should you be confident in the data if variability is high?
- How many data points (measurements) are needed for a desired level of
- How should you summarize the results of an experiment?
- How should you compare two systems using experimental data?
- What model best describes the relationships among components of a system?
What should I know?
- Sample vs. population and distribution
- Mean vs. sample mean
- Variance vs. sample variance
- Two famous distributions: uniform, normal
- Mean vs. median vs. mode.
- Quantile, percentile.
- Coefficient of variation.
Can you explain ...
- quote on top of pg. 182, "An alpha-quantile of a unit normal ...
has a N(0,1) distribution."
- Example 12.4
C. J. Ribbens,