Statistics
101Definitions
Home of www.mathoninfo.net
or The Mart or
Commercial PagesStatistics
101Definitions
Definitions
1. Statistics is the study of data.
2. Descriptive statistics describes a set of data.
3. Inferential statistics generates estimates and predictions from a set of data.
4. A population is a set of objects or events being studied.
5. A sample is a subset of the population.
6. A variable is a characteristic of each unit (element) of the population (such as height for the human population).
7. A statistical inference is an estimate or prediction.
8. Reliability of an estimate or prediction is a statement of its probability.
9. Quantitative data are data expressed in units of measure (such as distance).
10. Qualitative data are data expressed in categories.
(An example of quantitative data for a human population are the number of years of academic study completed; an example of qualitative data for a human population are the highest degrees obtained (bachelors, masters, doctorate.)
11. A representative sample is a sample that exhibits characteristics in proportion to those found within the population.
12. An unordered set is denoted by braces {}. For example, {5.4, 3.1, 2.2}. In unordered set notation, there appear no duplicates. An unordered set may be used, for example, to denote a set of possible outcomes in an experiment.
13. An ordered set is denoted by parentheses (). For example, (5.4, 3.1, 5.4, 2.2). In an ordered set, duplicates may appear; here, we see 5.4 twice. Ordered sets are often used to list observed data.
14. Parentheses () are also used to denote open intervals of real numbers, i.e., intervals of real numbers that do not include the endpoints. Examples are:
a. (0,1) denotes the set of all real numbers between 0 and 1, not including 0 and 1.
b. (1,
) denotes the set of all real numbers greater than 1.
c. (-
Open intervals may also be denoted using the notation a < x < b or x > a. The above examples in this notation are:
a. 0 < x < 1 denotes the set of all real numbers between 0 and 1, not including 0 and 1.
b. 1 < x <
Note that (1,
15. Brackets [] are used to denote closed intervals of real numbers, i.e., intervals of real numbers that include the endpoints. For example, [0,1] denotes the set of all real numbers between 0 and 1, including 0 and 1. Closed intervals may also be denoted using the notation a
x
16. A class is one of the categories into which a data set (population) can be put.
17. Class frequency is the data-set (population) count falling within the particular class.
18. Class relative frequency is the data-set (population) count falling within the particular class divided by the data-set total.
19. a. b. c. d. ... For a population of size n:
20. 21. 22. 23. 24. For a sample of size m:
25. 26. 27. 28. 29. 30. Approximately equals is denoted by
.
31. Percentages for a normal distribution and of a population:
a. The symbol %a(z1,z2) will be used to denote the percentage of the area under a normal curve (bell curve) that falls above the z-score interval (z1,z2).
b. The symbol %p(z1,z2) will be used to denote the percentage of a population with a trait falling within the z-score interval (z1,z2).
32. A population trait that has a histogram that is bell-shaped is often referred to as a bell-shaped distributed trait.
33. Percentile
a. The percentile of a selected measurement (quantitative datum) is that percent of the measurements (quantitative data) that fall at or below the selected measurement.
b. Also, the percentile of a selected population (or sample) member, with respect to some quantitative characteristic, is the percent of the population (or sample) whose measurements, with respect to the quantitative characteristic, fall at or below the measurement of the selected population (or sample) member.
c. Also, for p>0 and p
34. The first quartile or lower quartile of a quantitative data set is the 25th percentile of the data set, i.e., the smallest measurement such that at least 25% of all measurements within the data set fall at or below such smallest measurement. The first quartile is often designated by Q1 or QL; we will use Q1.
35. The third quartile or upper quartile of a quantitative data set is the 75th percentile of the data set, i.e., the smallest measurement such that at least 75% of all measurements within the data set fall at or below such smallest measurement. The first quartile is often designated by Q3 or QU; we will use Q3.
36. The interquartile range is equal to Q3 - Q1 and will be designated by IQR.
Choice Gifts for Birthday, Graduation, Mother's Day, Father's Day, Engagement, Anniversary, an Evening Out, or a Trip Abroad
Links to Amazon.com
Jewelry by Type: Earrings - Necklaces - Pendants - Brooches - Cufflinks - Money Clips Watches: Men's Watches - Men's Watches by Gucci - Men's Watches by Movado - Men's Watches by Tissot - Men's Watches by Cartier - Women's Watches - Women's Watches by Gucci - Women's Watches by Movado Thank you for visiting and patronizing Math on Info.
|
|
