Spring 2026--March 23th Jerry's Notes for statistics

 3.2

Result:

3.3

From this textbook.

Along with the center and the variability, another useful numerical measure is the ranking of a number. A percentile is a measure of ranking. It represents a location measurement of a data value to the rest of the values. Many standardized tests give the results as a percentile. Doctors also use percentiles to track a child’s growth.

The kth percentile is the data value that has k% of the data at or below that value.

Percentile: one of the points into which a large range of numbers, results, etc. is divided to make 100 groups of the same size  (From Cambridge dictionary)

kth percentile:  

$$

Is a measure in statistics indicating the value below which a given percentage (

$$

) of data points fall in an ordered dataset. It splits data into 100 equal parts, showing relative standing: if a score is in the 90th percentile, 90% of scores are lower.

EXP3.3.3 five-number summary for an even number of data points

Result

4.1: Empirical Probability

Event Space: the set of outcomes that make up an event. The symbol is usually a capital letter.

Law of large numbers: as n increases, the relative frequency tends towards the actual probability value. (Dice: 1~6 Point)

4.2: Theoretical Probability

1. What is the sample space?

Let H = head and T = tail, and list which can happen on each flip.

SS={HH, HT, TH, TT}