Procedure for random numbers

Procedure for random numbers

Does it describe the method for choosing the samples through the table of random numbers?

It Gets to azhar , based on no more than the size of the population numbers.

The steps to obtain a simple random sample are:
1 Define the study population .

2 List all units that make up the population analysis , assigning an identity number or identification.

3 Determine the optimal sample size for the study.

4 Choose systematically sampled using a table of random numbers generated by computational means to ensure that you have a ordenaleatorio.Por example, to get a taste of dragonfly which ainvestigar about What is most common color in my neighborhood ? .

You will then verify what color are 384 autos .

The first thing is to determine the random numbers. A list of enrolled students is obtained and assigned a number to each of them in alphabetical order and

upward . Assuming that the total is 3000 àlabras numbers 000,001 , 002, 003 are used , ... , 383 the sample size is determined , assuming that in this case is of size 384 .


 Then the table of random numbers four digits forming númerosde accepting unit of sample analysis to those who are between 000 and 384, higher numbers used should be disposed .







2 - . Does it mention and explain the components involved to determine the sample size ?

 Determine the level of confidence with which you want to work . ( Z ) where
z = 1.96 for 95% confidence oz = 1.65 for 90 % confidence

TABLE SUPPORT CALCULATION OF A SAMPLE SIZE
BY LEVEL OF CONFIDENCE
 certainty
95 %
94 %
93 %
92 %
91 %
90 %
80 %
62.27 %
50 %
Z
1.96
1.88
1.81
1.75
1.69
1.65
1.28
1
0.6745
*
3.84
3.53
3.28
3.06
2.86
2.72
1.64
1.00
0.45
and
0.05
0.06
0.07
0.08
0.09
0.10
0.20
0.37
0.50
*
0.0025
0.0036
0.0049
0.0064
0.0081
0.01
0.04
0.1369
0.25


 for example 95% of estimation and resulting z = 1.96
then :
  z = 1.65 to 90% .

Two . Estimate the characteristics of the investigated phenomenon. Where we consider the probability of the event ( p ) to occur and that is not performed ( q ) , always taking into account that the sum of both p + q values ​​will be invariably always equal to 1 if not count with sufficient information , we assign p = .50 q = .50
.
Three . Determine the maximum acceptable level of error in the results of the investigation. This can be up to 10% , since variations exceeding 10 % reduce the validity of the information.
April . The formula of the sample size is applied according to the type of population.
5.- value substitution .
6.- The value obtained is the number shows , I mean the number to investigate.

infinite population
Finite population
**
When the exact number is not known which comprises the population.
When you know how many elements the population
Where :
Z = confidence interval.
p = Probability favor .
q = Probability against.
N = Universe
e = error estimate.
n = sample size