1. Introduction
In the Bayesian inference techniques, GB analysis was introduced and studied based on the learning rate parameter (
). The traditional Bayesian framework for
is a fraction of the power of the likelihood function
for the parameter
. This means that if the prior distribution of the parameter
is
, then the GB posterior distribution for
is
For more information on the GB approach and how to select the value for the rate parameter, see [
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13]. Specifically, the choice of the learning rate was studied in [
3]- [
6] using the Safe Bayes algorithm based on the minimization of a sequential risk measure. In [
7] and [
8], another learning rate selection method was proposed, which included two different information adaptation strategies. The authors in [
12] investigated GBE based on a joint type-II censored sample from multiple exponential populations, using various values of the learning rate parameter. The same study was presented in [
13] but was based on joint hybrid censoring.
A one-sample prediction scheme is a Bayesian prediction method that determines the point predictor or prediction interval for unknown future values in the same sample based on the currently available observations. A two-sample prediction scheme or a multiple-sample prediction scheme are two other ways in which Bayesian prediction can utilize currently available observations to predict one or more future samples. Numerous authors have addressed the prediction of future failures or samples using different censoring techniques in the context of different prediction methods. We highlight some points that are relevant to our research. For instance, [
13] investigated the GBP using a combined type-II censored sample drawn from multiple exponential populations. A study using a joint type-II censored sample from two exponential populations for Bayes estimation and prediction was published in [
14]. Based on a generalized order statistic and multiple type II censoring, a Bayesian prediction for the future values of distributions from the class of exponential distributions was constructed in [
15,
16].
In the Bayesian study, the parameter of the distribution under investigation is a random variable, i.e. this unknown parameter is distributed according to the prior distribution. Empirical Bayes (EB) is a Bayesian study in which the parameters of the prior distribution (hyperparameters) are also unknown. By combining the density function of the distribution and the prior distributions, we obtain the marginal density function of the hyperparameters, which is used to estimate the hyperparameters. Therefore, the data of the original distribution are used to find the maximum likelihood estimators (MLEs) of these hyperparameters. EB has been introduced by many authors, for example, [
17] studied the EBE of reliability performances with progressive type-II censoring of the Lomax model. The reliability and hazard function of the Kumaraswamy distribution were determined by [
18] using progressive censored type II samples to estimate the EBE of the parameters. The Rayleigh distribution was studied in [
19] to determine EBE and EBP.
In this study, the GBE, GEBE, GBP and GEBP distributions from the class of exponential distributions were examined using type II censored samples. Thus, the aim of this study is to examine all GB and GEB results for different LRP values, including , which discribe the traditional Bayes.
The rest of this article is organized as follows.
Section 2 introduces the class of exponential models and then describes the problem of GB, GEB, GBP and GEBP for this class.
Section 3 applies the investigation from
Section 2 to the exponential and Rayleigh models, which are given as examples of the class. In addition, in that section, we present the simulation study for the exponential and Rayleigh models to obtain the GBE, GEBE, GBP and GEBP for different LRP values and compare the results. Finally,
Section 4 discusses the results and concludes the paper.
2. Estimation and Prediction
In this section, we introduce the exponential class of models and examine the problems of the GB, GEB, GBP, and GEBP for this class.
2.1. The Model
Let
be the vector of parameters, define a function
, and its derivative
where
The probability density function (pdf), the cumulative probability density function (cdf) and the survival function (sf) of the exponential class are each given by:
and
The likelihood function under type-II censored data from the class is given by,
where,
Consider the prior distribution of
in the following general form,
where,
, is a vector of hyperparameters.
Combining (4) and (5), after raising (4) to the fractional power
, the GB posterior distribution of
is given by,
where
and
2.2. Generalized empirical Bayesian estimation
Combining (1) and (5), to get the marginal pdf
as follows
From pdf in (8) we get the cdf
, then the likelihood function under type-II censored data is given by,
Using the loglikelihood function
, to find the maximum likelihood estimator (MLE)
as follows
By solving the following equation,
Substituting by
in (6) we obtain the posterior GE as follows,
2.3. A one sample prediction scheme
To determine the GBP and GEBP intervals using a one-sample prediction scheme under the type-II censored sample from the class, the first
ordered statistics
are observed from a random sample of size
A one sample prediction scheme is considered to predict the rest of unobserved values
The conditional density function of
given
is given by
Substituting by (1), (3) in (14), the conditional density function of
given
is,
where,
Combining (6) and (15) then integrating with respect to
, the GB predictive density function is given by,
The predictive reliability function of
is given by,
Equating (17) to , respectively, we obtain ( GBP bounds . GEBP bounds , can be obtained by substituting by in (17) then equating to .
3. Applications
In this section, we apply the results in the previous section to one parameter models, therefore the models that discussed here are exponential
and Rayliegh
. For these two distributions, the parameter
assumed to be unknown, we may consider the conjugate prior distribution of
as gamma prior distribution,
, hence,
3.1. Exponential model
Here we give the essential functions and important forms derived in
Section 2 for the exponential model as follows:
For the likelihood function we have
Generalized posterior function, can be formed from the following,
The GBE of the parameter
is given by,
The predictive reliability function of
is given by,
Equating (21) to , respectively, we obtain ( GBP bounds .
The functions and forms under GEB study can be illustrated as follows:
The marginal pdf
is given in the following form,
Using pdf
and cdf
we get the likelihood function based on type-II censored data, as follows,
By differentiating the loglikelihood function w. r. to and equating each equation to zero, then solving them numerically we get the estimators .
The GEBE of the parameter
is given by,
The predictive reliability function of
is given by,
Equating (25) to , respectively, we obtain ( GEBP bounds .
3.2. Rayleigh model
The essential functions and important forms derived in Section. 2 and Section. 3 for Rayliegh distribution are derived as follows:
For the likelihood function we have
Generalized posterior function, can be formed from the following,
The GBE of the parameter
is given by,
The predictive reliability function of
is given by,
Equating (28) to , respectively, we obtain ( GBP bounds .
The marginal pdf
is given in the following form,
Using pdf
and cdf
we get the likelihood function based on type-II censored data, as follows:
By differentiating the loglikelihood function with respect to and equating each equation to zero, then solving them numerically we get the estimators .
The GEBE of the parameter
is given by,
The predictive reliability function of
is given by,
Equating (31) to , respectively, we obtain ( GEBP bounds .
3.3. Numerical analysis
In this subsection, the results of the Monte Carlo simulation are presented to evaluate the performance of the inference methods derived in the previous sections.
The simulation study is designed and carried out for the two models as follows:
Generate one sample from each distribution with size , and choosing .
Based on the chosen values of the hyperparameters the suggested value for the parameter is , is obtained as the mean of gamma distribution in (18).
For EB, we use MLE
to compute
, where the results MLE
based on exponential and Rayliegh distributions are shown in
Table 1.
For the Monte Carlo simulations we use replicates, therefore the estimator , and the estimated risk,
Using (20), (24), (27) and (31), the estimation results are obtained and expressed by the estimator and ER for different values of LRP, where .
The results of GBE and GEBE for exponential and Rayliegh distributions are shown in
Table 2 and
Table 4.
Prediction results are based on one sample from each distribution with size , the number of observations is we then compute the GBP, GEBP bounds and its lengths at for the future values with using (28) and (32).
The results of GBP and GEBP for exponential and Rayliegh distributions are shown in
Table 3 and
Table 5.
From
Table 2. According to
and
ER, GBE becomes better for small value of LRP but for the large value of
, that means getting the best result at
and
(complete sample). GEBE becomes better for large value of LRP and for the large value of
, that means getting the best result at
and
In general the result of GBE is better than that of GEBE.
From
Table 3. According to the length of the interval
, GBP and GEBP becomes better for large value of
LRP, that means getting the best result at
and
(complete sample). In general, the result of GEBP is better than that of GBP.
From
Table 4. GBE becomes better for small value of LRP but for the large value of
, that means getting the best result at
and
(complete sample). GEBE becomes better for large value of LRP and for the large value of
, except for the complete sample, the result becomes better for small value of LRP that means getting the best result at
and
The result of GBE is better than that of GEBE at
, but GEBE is better than GBE for the complete sample.
From
Table 5. GBP and GEBP becomes better for large value of
LRP, that means getting the best result at
and
(complete sample). In general, the result of GEBP is better than that of GBP.
4. Discussion and Conclusion
In this study, a one-parameter model belonging to the class of exponential models is considered. Two well-known models
and
are examined based on a censored type-II sample. GB, GEB, GBP and GEBP are discussed for the two distributions with different values of LRP
. From the results in
Table 2 to
Table 5, we can summarize the results of the two distributions as follows:
4.1. The result of exponential model
GBE becomes better for small value of LRP but for the large value of , that means getting the best result at and . GEBE becomes better for large value of LRP and for the large value of , that means getting the best result at and
GBP and GEBP becomes better for large value of LRP, that means getting the best result at and .
The result of GBE is better than that of GEBE but the result of GEBP is better than that of GBP.
Small values of LRP give the best result for GBE but vice versa for GEBP.
4.2. The result of Rayleigh model
GBE becomes better for small value of LRP but for the large value of , that means getting the best result at and . GEBE becomes better for large value of LRP and for the large value of , except for the complete sample the result becomes better for small value of LRP, that means getting the best result at and The result of GBE is better than that of GEBE at , but GEBE is better than GBE for the complete sample.
GBP and GEBP becomes better for large value of LRP, that means getting the best result at and .
The result of GBE is better than that of GEBE but the result of GEBP is better than that of GBP.
Small values of LRP for the complete sample give the best result for GBE but vice versa for GEBP.
Funding
Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2024R226), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
Data Availability Statement
The data used to support the findings of this study are included in the article.
CRediT authorship contribution statement
Yahia Abdel-Aty: Project administration, Methodology, Investigation. Mohamed Kayid: Writing – original draft, Formal analysis, Data curation, Conceptualization. Ghadah Alomani: Writing – review & editing, Supervision, Software, Resources, Funding acquisition.
Declaration of competing interest:
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ghadah Alomani reports financial support was provided by Princess Nourah bint Abdulrahman University. Ghadah Alomani reports a relationship with Princess Nourah bint Abdulrahman University that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
The authors would like to thank the three anonymous reviewers for their thorough review of our article and their numerous comments and recommendations. The authors extend their sincere appreciation to Princess Nourah bint Abdulrahman University Researchers Supporting Project Number (PNURSP2024R226), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
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Table 1.
The MLEs of the hyperparameters under different data from the two distributions.
Table 1.
The MLEs of the hyperparameters under different data from the two distributions.
|
|
|
|
|
|
(20, 15) (50, 30) (50, 40) (50, 50) |
(10.497, 4.1) |
|
(10.95,4.625) |
(11.31, 4.926) |
|
(11, 4.4252) |
(10.9, 5.218) |
|
(10.995, 5.1456) |
(10.3, 5.289) |
|
(10.5, 5.2727) |
Table 2.
GBE and GEBE for the parameter of exponential distribution.
Table 2.
GBE and GEBE for the parameter of exponential distribution.
|
|
|
|
|
|
30 40 50 |
0.1 |
2.0491 |
0.0033 |
2.2308 |
0.0070 |
2.0436 |
0.0027 |
2.0687 |
0.0064 |
2.0295 |
0.0023 |
1.9677 |
0.0067 |
30 40 50 |
0.5 |
2.0611 |
0.0078 |
2.1430 |
0.0058 |
2.0461 |
0.0052 |
2.0526 |
0.0053 |
2.0401 |
0.0046 |
2.0052 |
0.0047 |
30 40 50 |
1 |
2.0655 |
0.0127 |
2.1119 |
0.0051 |
2.0495 |
0.0111 |
2.0495 |
0.0046 |
2.0414 |
0.0078 |
2.0187 |
0.0035 |
Table 3.
GBP and GEBP bound for exponential future values.
Table 3.
GBP and GEBP bound for exponential future values.
s |
|
|
length |
|
length |
16 18 20 |
0.1 |
(0.6596, 1.1826) |
0.5230 |
(0.6591, 1.0062) |
0.3471 |
(0.7282, 2.1919) |
1.4637 |
(0.7178, 1.6180) |
0.9002 |
(0.9338, 4.9415) |
4.0077 |
(0.8992, 3.3181) |
2.4189 |
16 18 20 |
0.5 |
(0.6597, 1.0920) |
0.4323 |
(0.6592, 1.0142) |
0.3550 |
(0.7321,1.8567) |
1.1246 |
(0.7237, 1.6225) |
0.8988 |
(0.9557, 3.9800) |
3.0243 |
(0.9251, 3.3245) |
2.3994 |
16 18 20 |
1 |
(0.6596, 1.0642) |
0.4046 |
(0.6593, 1.0181) |
0.3588 |
(0.7337, 1.7554) |
1.0217 |
(0.7273, 1.6225) |
0.8952 |
(0.9653, 3.6914)
|
2.7261
|
(0.9411, 3.3220)
|
2.3809
|
Table 4.
GBE and GEE for the parameter of Rayleigh distribution.
Table 4.
GBE and GEE for the parameter of Rayleigh distribution.
r |
|
|
|
|
|
30 40 50 |
0.1 |
2.0131 |
0.0028 |
2.3676 |
0.0129 |
2.0124 |
0.0023 |
2.1026 |
0.0082 |
2.0122 |
0.0013 |
1.9992 |
0.0013 |
30 40 50 |
0.5 |
2.0415 |
0.0060 |
2.2088 |
0.0095 |
2.0321 |
0.0026 |
2.0677 |
0.0048 |
2.0311 |
0.0024 |
2.0166 |
0.0015 |
30 40 50 |
1 |
2.0514 |
0.0075 |
2.1532 |
0.0074 |
2.0436 |
0.0059 |
2.0603 |
0.0020 |
2.0349
|
0.0041
|
2.0260
|
0.0018
|
Table 5.
GBP and GEBP bound for Rayleigh future values.
Table 5.
GBP and GEBP bound for Rayleigh future values.
s |
|
|
length |
|
length |
16 18 20 |
0.1 |
(1.1379, 1.5297) |
0.3918 |
(1.1376, 1.4252) |
0.2876 |
(1.1967, 2.0880) |
0.8913 |
(1.1914, 1.8238) |
0.6324 |
(1.3577, 3.1400) |
1.7823 |
(1.3448, 2.6322) |
1.2874 |
16 18 20 |
0.5 |
(1.1379, 1.4695) |
0.3316 |
(1.1377, 1.4253) |
0.2876 |
(1.2000, 1.9209) |
0.7209 |
(1.1954, 1.8145) |
0.6191 |
(1.3738, 2.8175) |
1.4437 |
(1.3597, 2.6121) |
1.2524 |
16 18 20 |
1 |
(1.1379, 1.4507) |
0.3128 |
(1.1378, 1.4251) |
0.2873 |
(1.2013, 1.8674) |
0.6661 |
(1.976, 1.8084) |
0.6108 |
(1.3807, 2.7132) |
1.3325 |
(1.3689, 2.5993) |
1.2304
|
|
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