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I International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456nternational Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470
nd
Special Issue of Special Issue of 2 International Congress of Engineering
 Model timing. Once the production process was Once the production process was
studied, samples of each activity were made. We studied, samples of each activity were made. We
The formula developed is as follows:he formula developed is as follows:
used the formula of Dr. Bolaños (2012), who used the formula of Dr. Bolaños (2012), who T
proposes the following formula for an infinite proposes the following formula for an infinite
sample: n  . 1 ( 645 ) 2 * 5 . 0 * 5 . 0  67 65.7  67 . 65  68
6
. 0 ( 10 ) 2 . 0 01
Z 2 * p *q
n   The study indicated that for the investigation of the he study indicated that for the investigation of the
T
i 2 production process, using 90% of reliability and 10% oduction process, using 90% of reliability and 10%
pr
Where: of
of allowed error, 68 observatio allowed error, 68 observations or time takings will
be needed for the investigation. needed for the investigation.
be
n: sample size.
z: value corresponding to gauss distribution, 90% z: value corresponding to gauss distribution, 90% Also, once it is known how many time takers should lso, once it is known how many time takers should
A
(1,645) was used for the study. be
be made for the investigation, it was carried out. made for the investigation, it was carried out.
p: expected prevalence of the parameter to be p: expected prevalence of the parameter to be F
Figure 3 represents an example of the timing of each igure 3 represents an example of the timing of each
evaluated, if not known (p = 0.5), which increases the evaluated, if not known (p = 0.5), which increases the activity.
sample size
q: 1 - p (if p = 70%, q = 30%)
i: error expected to be committed if it is 10%, i = 0.: error expected to be committed if it is 10%, i = 0.

Figure 3. Example of model timingsFigure 3. Example of model timings

 Validation of model timings. At this stage it was At this stage it was  : standard deviation of the preliminary sample.: standard deviation of the preliminary sample.
i
validated whether sixty-eight preliminary samples eight preliminary samples i: error expected to be committed in the study. The : error expected to be committed in the study. The
were more than sufficient for the study. All samples were more than sufficient for the study. All samples error is set to integer.
of each activity of the production process were n process were
I
validated, the formula used was as follows:validated, the formula used was as follows: It is worth mentioning that, if the result of the formula t is worth mentioning that, if the result of the formula
i
is smaller than the size of the preliminary sample,s smaller than the size of the preliminary sample, the
study is considered good or sufficient. Otherwise, if tudy is considered good or sufficient. Otherwise, if
 Z *  2 s
t
n    the number of the formula is greater than the size of he number of the formula is greater than the size of
t
 e 2  the preliminary sample, the study is not suffering, he preliminary sample, the study is not suffering,


which means that samples are missing to perform for hich means that samples are missing to perform for
w
Where: the study to be complete.

n: number of samples needed for the study.n: number of samples needed for the study. The development of the formula for the warehouse ent of the formula for the warehouse
Z: value corresponding to the gauss distribution, for Z: value corresponding to the gauss distribution, for activity is as follows:
the investigation Z = 95%, which is equal to 1.96.the investigation Z = 95%, which is equal to 1.96.

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