What symbol does the power supply use

What symbol does the power supply use

The symbol of DC is + - and the symbol of AC power is ∽

What is the symbol for the hour

h
It's the abbreviation of hour

What symbol is MeV? How many times is ev

MeV energy unit
1000000x

On the meaning of several statistical symbols
There's this ^ sign on the top of P

Is that X-bar the subscript of S? If the capital s, it represents the standard deviation of the population mean; if the small s, it represents the standard deviation of the sample mean
The symbol above P represents the predicted or estimated value

How to convert physical composite units

(1) First, translate the compound unit into ratio, (2) convert the numerator and denominator respectively, and break each one, (3) synthesize the new unit and combine the numbers, (4) get the result. For example: 1kg / m ^ 3 = 1kg / 1m ^ 3 ----- (1) = 1000g / 1000000cm ^ 3 ----- (2) = (1 / 1000) (g / m ^ 3) -- (3) 1g / cm ^ 3 = 1000kg / m ^ 3 --

Meaning of statistical e symbol
What do n above, I = 1 below and the following stand for?

E is expectation,
Xi refers to all possible values of discrete random variables, n is the number of all possible values, then I can take n from 1, (I = 1,2,..., n-1, n)
Therefore, e is the sum of the product of all possible values Xi of discrete random variables and the probability Pi of the occurrence of this value. It can also be said to be the weighted average
Just as we usually calculate the assessment score, the assessment items a and B are 60 and 40 respectively, but their contribution rates (which can be understood as the probability of occurrence) are 20% and 80% respectively, then E = 60x20% + 40x80% = 44. Of course, these are two different concepts, but the calculation method can be used for reference

Can you explain the atomic unit in detail?
I mean, in terms of atomic time scale, can it be abbreviated as?

The minimum space area of an object. It contains the composite circular motion of the supporting structure

Definition and relationship of indicators, indicators and variables

Indicators reflect the quantitative characteristics of the statistical population, and signs reflect the characteristics of the overall unit
Indicators are divided into quantitative indicators and quality indicators
Quantitative indicators, reflecting the overall scale or level, such as population, output, arable land area
Quality indicators reflect the total internal quality, such as product qualification rate, labor productivity, etc
Mark is divided into quality mark and quantity mark
Quality marks, such as gender, native place, etc
Quantity mark, person's age, height, employee's salary, etc
Relationship: 1. The index reflects the whole, and the mark reflects the unit;
2. The expression method is different (text or number);
3. Mark is the basis of index, and index is the summary of mark
Such as a classmate, gender female, female is the symbol of a, B classmate, gender male, male is the symbol of B Suppose there are five male students and three female students, and the ratio of male to female is 5:3. This 5:3 is the indicator. Without the gender mark of each student in front, we can't get the following 5:3 by summation
I'm so tired of typing. Did you give me five points?

The initial kinetic energy is 5MeV,

MeV = MeV
Einstein photoelectric effect equation: EK = h ν - w (EK is the maximum initial kinetic energy of photoelectron, W is the work of escape)

In statistics, what are the relations and differences between statistical indicators and indicators?

I'm glad to answer your question: statistical indicators are used to describe the comprehensive quantitative characteristics of the population. Statistical indicators are used to describe the name of the overall unit characteristics. The differences are as follows: 1) indicators are used to describe the overall unit characteristics, and indicators are used to describe the overall characteristics; 2) indicators can be expressed by numerical values, and the quality indicators in the indicators