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This section is about the symbols of probability statistics. |
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1)P (A) | Probability function. | Probability of event A. | P(A) = 0.5 |
2) P(A∩ B) | Probability of events intersection | Probability that of events A and B | P(A∩B) = 0.6 |
3) P(A ∪ B) | Probability of events union | Probability that of events A or B | P(A∪B) = 0.9 |
4) P(A | B) | Conditional probability function | Probability of event A given event B occurred | P(A | B) = 0.2 |
5) f (x) | Probability density function (pdf) | P(a ≤ x ≤ b) = ∫ f (x) dx | |
6) F(x) | Cumulative distribution function (cdf) | F(x) = P(X ≤ x) | |
7) μ | Population mean | Mean of population values | μ = 20 |
8) E(X) | Expectation value | Expected value of random variable X | E(X) = 20 |
9) E(X | Y) | Conditional expectation | Expected value of random variable X given Y | E(X | Y=2) = 5 |
10) var(X) | Variance | Variance of random variable X | var(X) = 4 |
11) σ2 | Variance | Variance of population values | σ2 = 9 |
12) std(X) | Standard deviation | Standard deviation of random variable X | std(X) = 2 |
13) σ x | Standard deviation | Standard deviation value of random variable X | σx = 2 |
14)x˜ | Median | Middle value of random variable x | x˜=6 |
15) cov(X,Y) | Covariance | Covariance of random variables X and Y | cov(X,Y) = 6 |
16) corr(X,Y) | Correlation | Correlation of random variables X and Y | corr(X,Y) = 3 |
17) ρX,Y | Correlation | Correlation of random variables X and Y | ρX,Y = 4 |
18) ∑ | Summation | Summation - sum of all values in range of series | ∑ Xi (i = 1 to 4) = x1+x2+x3+x4 |
19) Mo | Mode | Value that occurs most frequently in population | |
20) MR | Mid-range | MR = (xmax+xmin)/2 | |
21) Md | Sample median | Half the population is below this value | |
22) Q1 | Lower / first quartile | 25% of population are below this value | |
23) Q2 | Median / second quartile | 50% of population are below this value = median of samples | |
24) Q3 | Upper / third quartile | 75% of population are below this value | |
25) X- | Sample mean | Average / arithmetic mean | x- = (2+5+9) / 3 = 5.333 |
26) s2 | Sample variance | Population samples variance estimator | s2 = 9 |
27) s | Sample standard deviation | Population samples standard deviation estimator | s = 4 |
28) zx | Standard score | zx = (x-x) / sx | |
29) X ~ | Distribution of X | Distribution of random variable X | X ~ N(0,4) |
30) N(μ,σ2) | Normal distribution | Gaussian distribution | X ~ N(0,6) |
31) U(a,b) | uniform distribution | equal probability in range a,b | X ~ U(0,8) |
Russia-Ukraine crisis update - 3rd Mar 2022
The UN General assembly voted at an emergency session to demand an immediate halt to Moscow's attack on Ukraine and withdrawal of Russian troops.