The calculation of the average arithmetical number.

a) Average arithmetic simple number M is calculated, when the frequencies are equal to 1 or are equal between them. The average arithmetic number simple is the algebraic sum of variants divided by number of observations. For example, we have the following variation set:

n =f

15-1

18-1

24-1

27-1

Where V – variants are numbers of the bed-days (spent by patients at the age of 50 years old), f-frequency, n-number of observations (the whole number of patients is 4)

 

 

b) Average arithmetical number suspension is directly proportional to the algebraic sum of variation their frequencies and indirectly proportional to the total of observations.

Average arithmetical number suspension is calculated when the frequencies are not equal between them.

c) Average arithmetical number according to the way of moments:

D- average arithmetical deviation of every variant from the conditional average,

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Table 15

Algorithm of average number estimation

 

V	f	d= V-Xo	df	d²	d²f
Sdf					Sd^2f

 

Calculation of an average quadratic deviation describing a variety of signs.

The average quadratic deviation characterizes a degree of dispersion of a variation set around the average.

a) Simple

f< 1, n > 30

 

b) Suspension
f ≥ 1, n ≥ 30

c) According to the way of the moments

f ≥ 1, 100 < n ≥ 30

 

d) According (express) way

It is more typical, but the more exact is the average number.

1. Calculation of an average mistake of an average arithmetical number.

The average mistake of average arithmetical number is directly proportional to an average quadratic deviation and indirectly proportional to the square root of the number of observations.

 

2. Coefficient of a variation (Cv):

It is calculated in comparison of 2 different continuous and non-continuous variation sets

Weak variety of signis when Cv=10%.

Average variety of signis when Cv=10-25%.

Strong variety of signis when Cv>25%

 

Main questions:

1. What is variation set?

2. What are the parameters of variation set and their characteristics?

3. What are the kinds of variation set?

4. Average number and its kinds.

5. Methods of counting of average number.

6. Criteria of variety of the sign in total

7. Calculation of an average quadratic deviation.

8. Calculation of coefficient of a variation.

9. Evaluation of coefficient of a variation.

Situation tasks.

VARIANT 1.

Table 16