# Control Chart for Failure-Censored Reliability Tests under Uncertainty Environment

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## Abstract

**:**

## 1. Introduction

## 2. State of the Art

- Choose a random sample of the size ${n}_{N}\u03f5\left\{{n}_{L},{n}_{U}\right\}$ and begin the test. Continue with the test until ${r}_{N}$ are reached and note the ith failure time, say ${X}_{\left(iN\right)}$ (i = 1, …, ${r}_{N}$).
- Compute the following statistic under NSIM:$${v}_{N}={{\displaystyle \sum}}_{i=1}^{{r}_{N}}{\left(\frac{{X}_{\left(iN\right)}}{{\mu}_{0N}}\right)}^{{m}_{N}}+\left({n}_{N}-{r}_{N}\right){\left(\frac{{X}_{\left(iN\right)}}{{\mu}_{0N}}\right)}^{{m}_{N}};{m}_{N}\u03f5\left\{{m}_{L},{m}_{U}\right\},{\lambda}_{N}\u03f5\left\{{\lambda}_{L},{\lambda}_{U}\right\}$$
- Declare the process in the control state if ${\mathrm{LCL}}_{N}\le {v}_{N}\le {\mathrm{UCL}}_{N}$ where ${\mathrm{LCL}}_{N}$ and ${\mathrm{UCL}}_{N}$ denote the neutrosophic lower control limit (NLCL) and neutrosophic upper control limit (NUCL), respectively.

- Specify ${m}_{N}\u03f5\left\{{m}_{L},{m}_{U}\right\}$, ${\lambda}_{N}\u03f5\left\{{\lambda}_{L},{\lambda}_{U}\right\}$ and ${r}_{N}\u03f5\left\{{r}_{L},{r}_{U}\right\}$.
- Specify ${r}_{0N}\u03f5\left\{{r}_{L},{r}_{U}\right\}$ and determine the neutrosophic control limits such that ${\mathrm{NARL}}_{0\mathrm{N}}\ge {r}_{0N}$.
- Several combinations exist that satisfy the condition ${\mathrm{NARL}}_{0\mathrm{N}}\ge {r}_{0N}$. However, choose the combination of the neutrosophic parameters where ${\mathrm{NARL}}_{0\mathrm{N}}$ is very close to ${r}_{0N}$.
- Use neutrosophic control limits to find ${\mathrm{NARL}}_{1\mathrm{N}}\u03f5\left\{NAR{L}_{1L},NAR{L}_{1U}\right\}$.

## 3. Advantages of the Proposed Chart

_{1}. The values of ${\mathrm{NARL}}_{1\mathrm{N}}$ from the proposed control chart under NISM and ARL

_{1}from Aslam et al. [34] under the classical statistics are in Table 5 at the same levels of all specified control chart parameters. From Table 5, we note that the proposed control chart has the values of ${\mathrm{NARL}}_{1\mathrm{N}}$ in the indeterminacy interval while the existing control chart under the classical statistics provides only the determined values of ARL

_{1}. For example, when $c$ = 0.1, we have ${\mathrm{NARL}}_{1\mathrm{N}}=1.45+1.45I;I\u03f5\left\{0,7.09\right\}$. Thus, the determinate par is ARL

_{1}= 1.45 and the indeterminate part is $1.45I;I\u03f5\left\{0,7.09\right\}$. Therefore, the indeterminacy interval of ${\mathrm{NARL}}_{1\mathrm{N}}$ is ${\mathrm{NARL}}_{1\mathrm{N}}=\left[10.287,1.451\right];I\u03f5\left\{0,7.09\right\}$. From this example, it is clear that the proposed control chart has determinate and indeterminate information under the indeterminate situation. Therefore, the proposed control chart is more effective under the indeterminate situation than Aslam et al. [34] chart, which is a special case of the proposed chart.

## 4. Case Study

_{L}that needs special attention by the industrial engineers. However, the existing control chart indicates that only two values are very close to the control limit. By comparing Figure 3 with Figure 4, we conclude that the proposed control chart is better, more flexible, and more effective than the existing chart under the uncertainty environment. In addition, the proposed control chart is more efficient for the monitoring of the process than the existing control chart.

## 5. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 2.**Aslam et al. [34] control chart for the simulated data.

**Figure 4.**Aslam et al. [34] control chart for the automobile data.

**Table 1.**The values of NARL when ${m}_{N}=\left[0.4,0.6\right]$ and ${\lambda}_{N}=\left[0.45,0.55\right]$.

Neutrosophic Control Limits | ${\mathit{r}}_{\mathit{N}}=\left[2,5\right]$ | ||
---|---|---|---|

${\mathrm{LCL}}_{N}$ | [0.0595, 0.778] | [0.0484, 0.708] | [0.0401, 0.621] |

${\mathrm{UCL}}_{N}$ | [6.1131, 11.498] | [6.6267, 11.801] | [6.0133, 11.331] |

$c$ | ${\mathrm{NARL}}_{1\mathrm{N}}$ | ||

0.1 | [10.28, 1.45] | [13.43, 1.49] | [9.81, 1.43] |

0.2 | [28.02, 2.91] | [40.55, 3.11] | [26.63, 2.81] |

0.3 | [57.00, 6.20] | [88.45, 6.86] | [55.42, 5.87] |

0.4 | [95.77, 13.22] | [155.28, 15.12] | [98.58, 12.32] |

0.5 | [137.44, 27.61] | [226.82, 32.64] | [155.05, 25.52] |

0.6 | [172.70, 55.32] | [283.97, 67.72] | [218.65, 51.63] |

0.7 | [195.74, 102.02] | [316.96, 130.22] | [279.38, 100.34] |

0.75 | [202.48, 131.52] | [324.90, 172.01] | [305.64, 136.51] |

0.8 | [206.48, 161.66] | [328.31, 216.90] | [328.06, 181.27] |

0.85 | [208.20, 188.06] | [328.22, 258.76] | [346.29, 233.11] |

0.9 | [208.11, 206.64] | [325.53, 290.79] | [360.32, 287.91] |

0.92 | [207.68, 211.35] | [323.91, 299.73] | [364.80, 309.24] |

0.95 | [206.66, 215.43] | [321.01, 308.62] | [370.39, 339.15] |

0.98 | [205.29, 216.16] | [317.68, 312.24] | [374.70, 365.18] |

0.99 | [204.76, 215.74] | [316.49, 312.36] | [375.88, 372.78] |

1 | [204.20, 215.021] | [315.26, 311.99] | [376.92, 379.77] |

1.1 | [197.40, 196.27] | [301.78, 288.42] | [381.40, 413.47] |

1.2 | [189.38, 168.95] | [287.42, 248.89] | [377.72, 392.50] |

1.3 | [181.06, 142.89] | [273.34, 210.15] | [369.13, 347.01] |

1.4 | [172.94, 120.90] | [260.06, 177.26] | [357.92, 298.46] |

1.5 | [165.25, 103.03] | [247.76, 150.53] | [345.55, 255.18] |

1.6 | [158.07, 88.61] | [236.47, 129.01] | [332.90, 218.90] |

1.7 | [151.42, 76.92] | [226.14, 111.61] | [320.47, 189.04] |

1.8 | [145.30, 67.36] | [216.70, 97.42] | [308.54, 164.53] |

1.9 | [139.65, 59.47] | [208.06, 85.73] | [297.23, 144.29] |

2 | [134.44, 52.89] | [200.13, 76.01] | [286.60, 127.46] |

2.5 | [113.69, 32.17] | [168.76, 45.55] | [242.88, 75.01] |

3 | [99.01, 21.79] | [146.74, 30.45] | [211.32, 49.30] |

4 | [79.63, 12.21] | [117.73, 16.65] | [169.38, 26.17] |

5 | [67.30, 8.05] | [99.31, 10.76] | [142.69, 16.46] |

6 | [58.70, 5.87] | [86.47, 7.69] | [124.09, 11.50] |

**Table 2.**The values of NARL when ${m}_{N}=\left[0.9,1.10\right]$ and ${\lambda}_{N}=\left[0.45,0.55\right]$.

Neutrosophic Control Limits | ${\mathit{r}}_{\mathit{N}}=\left[2,5\right]$ | ||
---|---|---|---|

${\mathrm{LCL}}_{N}$ | [0.0865, 1.08] | [0.0693, 0.961] | [0.0621, 0.933] |

${\mathrm{UCL}}_{N}$ | [8.7698, 16.05] | [9.1713, 16.073] | [9.2462, 17.103] |

$c$ | ${\mathrm{NARL}}_{1\mathrm{N}}$ | ||

0.1 | [1.47, 1.01] | [1.51, 1.00] | [1.52, 1.00] |

0.2 | [2.73, 1.14] | [2.92, 1.14] | [2.96, 1.12] |

0.3 | [5.42, 1.64] | [6.05, 1.64] | [6.17, 1.55] |

0.4 | [11.04, 2.96] | [12.83, 2.97] | [13.21, 2.66] |

0.5 | [22.54, 6.42] | [27.35, 6.46] | [28.43, 5.44] |

0.6 | [45.01, 15.99] | [57.26, 16.15] | [60.31, 12.76] |

0.7 | [84.15, 43.51] | [112.87, 44.57] | [121.43, 33.20] |

0.75 | [109.92, 71.90] | [151.64, 75.13] | [165.63, 54.94] |

0.8 | [137.49, 114.27] | [195.01, 124.35] | [216.93, 91.1923033] |

0.85 | [163.49, 165.47] | [237.85, 193.61] | [270.02, 148.57] |

0.9 | [184.36, 206.18] | [273.92, 266.89] | [317.40, 228.62] |

0.92 | [190.70, 214.58] | [285.30, 289.78] | [333.15, 264.14] |

0.95 | [197.82, 217.32] | [298.53, 310.99] | [352.37, 314.84] |

0.98 | [202.13, 210.10] | [307.11, 314.91] | [365.94, 354.61] |

0.99 | [202.98, 206.08] | [308.97, 312.77] | [369.22, 364.14] |

1 | [203.55, 201.49] | [310.37, 309.19] | [371.89, 371.54] |

1.1 | [197.60, 145.94] | [304.06, 235.50] | [371.27, 343.99] |

1.2 | [180.35, 101.35] | [277.91, 163.84] | [342.17, 250.67] |

1.3 | [161.00, 71.96] | [247.86, 115.38] | [306.11, 177.06] |

1.4 | [143.14, 52.65] | [220.06, 83.59] | [272.03, 127.50] |

1.5 | [127.65, 39.62] | [195.98, 62.26] | [242.29, 94.23] |

1.6 | [114.45, 30.55] | [175.50, 47.53] | [216.92, 71.35] |

1.7 | [103.22, 24.08] | [158.11, 37.08] | [195.36, 55.21] |

1.8 | [93.64, 19.35] | [143.28, 29.49] | [176.96, 43.55] |

1.9 | [85.40, 15.82] | [130.53, 23.86] | [161.16, 34.95] |

2 | [78.26, 13.13] | [119.51, 19.60] | [147.48, 28.49] |

2.5 | [53.68, 6.21] | [81.58, 8.83] | [100.47, 12.32] |

3 | [39.61, 3.67] | [59.90, 4.97] | [73.63, 6.67] |

4 | [24.73, 1.92] | [37.06, 2.38] | [45.38, 2.97] |

5 | [17.31, 1.37] | [25.72, 1.58] | [31.38, 1.85] |

6 | [13.03, 1.15] | [19.20, 1.26] | [23.33, 1.40] |

**Table 3.**The values of NARL when ${m}_{N}=\left[2.4,2.6\right]$ and ${\lambda}_{N}=\left[0.45,0.55\right]$.

Neutrosophic Control Limits | ${\mathit{r}}_{\mathit{N}}=\left[2,5\right]$ | ||
---|---|---|---|

${\mathrm{LCL}}_{N}$ | [0.119, 1.27] | [0.106, 1.07] | [0.0882, 0.955] |

${\mathrm{UCL}}_{N}$ | [12.029, 18.76] | [13.87, 18.84] | [13.089, 18.984] |

$c$ | ${\mathrm{NARL}}_{1\mathrm{N}}$ | ||

0.1 | [1.00, 1.00] | [1.00, 1.00] | [1.00, 1.00] |

0.2 | [1.0, 1.00] | [1.02, 1.00] | [1.01, 1.00] |

0.3 | [1.09, 1.00] | [1.12, 1.00] | [1.11, 1.00] |

0.4 | [1.35, 1.01] | [1.47, 1.01] | [1.42, 1.01] |

0.5 | [2.03, 1.09] | [2.41, 1.09] | [2.24, 1.09] |

0.6 | [3.85, 1.44] | [5.19, 1.44] | [4.57, 1.45] |

0.7 | [9.45, 2.74] | [15.11, 2.77] | [12.40, 2.81] |

0.75 | [16.32, 4.52] | [28.77, 4.59] | [22.75, 4.70] |

0.8 | [29.86, 8.52] | [58.00, 8.7.00] | [44.56, 8.99] |

0.85 | [56.52, 18.41] | [117.97, 18.96] | [90.98, 19.80] |

0.9 | [104.00, 45] | [214.7, 47.4] | [180.79, 50.26] |

0.92 | [128.33, 65.61] | [254.10, 70.55] | [229.02, 75.59] |

0.95 | [164.80, 113.08] | [295.89, 129.5] | [302.41, 142.57] |

0.98 | [191.91, 173.85] | [307.79, 226.65] | [355.84, 263.97] |

0.99 | [197.40, 191.41] | [305.72, 264.90] | [366.03, 317.43] |

1 | [200.93, 204.62] | [301.36, 302.15] | [372.12, 374.36] |

1.1 | [166.99, 127.68] | [214.78, 262.21] | [300.84, 411.25] |

1.2 | [114.56, 53.35] | [144.52, 106.83] | [204.15, 166.01] |

1.3 | [79.65, 24.85] | [100.14, 47.67] | [141.14, 72.39] |

1.4 | [57.02, 12.92] | [71.51, 23.63] | [100.48, 34.96] |

1.5 | [41.92, 7.41] | [52.44, 12.87] | [73.43, 18.52] |

1.6 | [31.55, 4.65] | [39.36, 7.64] | [54.91, 10.67] |

1.7 | [24.26, 3.16] | [30.16, 4.91] | [41.91, 6.63] |

1.8 | [19.00, 2.31] | [23.55, 3.38] | [32.59, 4.42] |

1.9 | [15.15, 1.81] | [18.70, 2.49] | [25.76, 3.14] |

2 | [12.26, 1.49] | [15.08, 1.94] | [20.67, 2.37] |

2.5 | [5.18, 1.03] | [6.23, 1.08] | [8.29, 1.14] |

3 | [2.82, 1.00] | [3.30, 1.00] | [4.23, 1.00] |

4 | [1.40, 1.00] | [1.54, 1.00] | [1.82, 1.00] |

5 | [1.08, 1.00] | [1.12, 1.00] | [1.21, 1.00] |

6 | [1.01, 1.00] | [1.02, 1.00] | [1.04, 1.00] |

**Table 4.**The values of NARL when ${m}_{N}=\left[2.40,2.60\right]$ and ${\lambda}_{N}=\left[1.90,2.10\right]$.

Neutrosophic Control Limits | ${\mathit{r}}_{\mathit{N}}=\left[2,5\right]$ | ||
---|---|---|---|

${\mathrm{LCL}}_{N}$ | [0.121, 1.36] | [0.109, 0.815] | [0.0908, 1.21] |

${\mathrm{UCL}}_{N}$ | [12.3, 19.9] | [15.135, 18.198] | [13.5992, 21.39] |

$c$ | ${\mathrm{NARL}}_{1\mathrm{N}}$ | ||

0.1 | [1.00, 1.00] | [1.00, 1.00] | [1.00, 1.00] |

0.2 | [1.01, 1.00] | [1.02, 1.00] | [1.02, 1.00] |

0.3 | [1.10, 1.00] | [1.15, 1.00] | [1.12, 1.00] |

0.4 | [1.37, 1.01] | [1.55, 1.00] | [1.45, 1.02] |

0.5 | [2.08, 1.11] | [2.72, 1.07] | [2.35, 1.14] |

0.6 | [4.02, 1.53] | [6.42, 1.39] | [4.97, 1.68] |

0.7 | [10.11, 3.18] | [20.95, 2.55] | [14.12, 3.89] |

0.75 | [17.71, 5.54] | [42.43, 4.10] | [26.61, 7.31] |

0.8 | [32.83, 11.15] | [89.79, 7.50] | [53.45, 16.03] |

0.85 | [62.65, 25.8] | [181.82, 15.73] | [110.80, 40.93] |

0.9 | [114.54, 66.39] | [294.62, 37.93] | [216.44, 117.07] |

0.92 | [140.01, 96.61] | [323.83, 56.07] | [268.18, 176.84] |

0.95 | [175.93, 156.06] | [337.46, 104.54] | [337.22, 294.34] |

0.98 | [199.53, 203.24] | [322.35, 200.44] | [375.37, 375.25] |

0.99 | [203.48, 208.65] | [313.57, 248.88] | [379.59, 379.24] |

1 | [205.45, 208.09] | [303.79, 307.56] | [379.96, 371.89] |

1.1 | [163.83, 98.63] | [203.67, 744.86] | [286.61,161.48] |

1.2 | [111.83, 41.49] | [136.53, 321.09] | [193.27, 65.86] |

1.3 | [77.73, 19.68] | [94.63, 136.05] | [133.63, 30.25] |

1.4 | [55.66, 10.43] | [67.61, 63.56] | [95.17, 15.48] |

1.5 | [40.93, 6.11] | [49.61, 32.46] | [69.59, 8.73] |

1.6 | [30.82, 3.92] | [37.26, 17.98] | [52.07, 5.38] |

1.7 | [23.70, 2.73] | [28.58, 10.71] | [39.77, 3.59] |

1.8 | [18.58, 2.04] | [22.33, 6.83] | [30.94, 2.58] |

1.9 | [14.81, 1.63] | [17.75, 4.64] | [24.47, 1.98] |

2 | [12.00, 1.38] | [14.33, 3.34] | [19.65, 1.61] |

2.5 | [5.08, 1.02] | [5.95, 1.29] | [7.92, 1.04] |

3 | [2.77, 1.00] | [3.17, 1.02] | [4.06, 1.00] |

4 | [1.39, 1.00] | [1.51, 1.00] | [1.77, 1.00] |

5 | [1.07, 1.00] | [1.11, 1.00] | [1.19, 1.00] |

6 | [1.01, 1.00] | [1.01, 1.00] | [1.04, 1.00] |

**Table 5.**The comparison of the proposed chart with the existing one when ${m}_{N}=\left[0.4,0.6\right],{\lambda}_{N}=\left[0.45,0.55\right],\text{}\mathrm{and}\text{}{r}_{N}=\left[2,5\right]$.

Neutrosophic Control Limits | Proposed Control Chart | Existing Control Chart | ||||
---|---|---|---|---|---|---|

$LC{L}_{N}$ | $NAR{L}_{0N}\in \left[200,200\right]$ | $NAR{L}_{0N}\in \left[300,300\right]$ | $NAR{L}_{0N}\in \left[370,370\right]$ | ARL = 200 | ARL = 300 | ARL = 370 |

$UC{L}_{N}$ | ||||||

$c$ | NARL_{1} | ARL_{1} | ||||

0.1 | [10.28, 1.45] | [13.43, 1.49] | [9.81, 1.43] | 1.45 | 1.49 | 1.43 |

0.2 | [28.02, 2.91] | [40.55, 3.11] | [26.63, 2.81] | 2.91 | 3.11 | 2.81 |

0.3 | [57.00, 6.20] | [88.45, 6.86] | [55.42, 5.87] | 6.20 | 6.86 | 5.87 |

0.4 | [95.77, 13.22] | [155.28, 15.12] | [98.58, 12.32] | 13.22 | 15.1 | 12.32 |

0.5 | [137.44, 27.61] | [226.82, 32.64] | [155.05, 25.52] | 27.61 | 32.6 | 25.52 |

0.6 | [172.70, 55.32] | [283.97, 67.72] | [218.65, 51.63] | 55.32 | 67.72 | 51.63 |

0.7 | [195.74, 102.02] | [316.96, 130.22] | [279.38, 100.34] | 102.02 | 130.22 | 100.34 |

0.75 | [202.48, 131.52] | [324.90, 172.01] | [305.64, 136.51] | 131.52 | 172.01 | 136.51 |

0.8 | [206.48, 161.66] | [328.31, 216.90] | [328.06, 181.27] | 161.66 | 216.90 | 181.27 |

0.85 | [208.20, 188.06] | [328.22, 258.76] | [346.29, 233.11] | 188.06 | 258.76 | 233.11 |

0.9 | [208.11, 206.64] | [325.53, 290.79] | [360.32, 287.91] | 206.64 | 290.79 | 287.91 |

0.92 | [207.68, 211.35] | [323.91, 299.73] | [364.80, 309.24] | 211.35 | 299.73 | 309.24 |

0.95 | [206.66, 215.43] | [321.01, 308.62] | [370.39, 339.15] | 215.43 | 308.62 | 339.15 |

0.98 | [205.29, 216.16] | [317.68, 312.24] | [374.70, 365.18] | 216.16 | 312.24 | 365.18 |

0.99 | [204.76, 215.74] | [316.49, 312.36] | [375.88, 372.78] | 215.74 | 312.36 | 372.78 |

1 | [204.20, 215.02] | [315.26, 311.99] | [376.92, 379.77] | 215.02 | 311.99 | 376.92 |

1.1 | [197.40, 196.27] | [301.78, 288.42] | [381.40, 413.47] | 196.27 | 288.42 | 381.40 |

1.2 | [189.38, 168.95] | [287.42, 248.89] | [377.72, 392.50] | 168.95 | 248.89 | 377.7 |

1.3 | [181.06, 142.89] | [273.34, 210.15] | [369.13, 347.01] | 142.89 | 210.15 | 347.01 |

1.4 | [172.94, 120.90] | [260.06, 177.26] | [357.92, 298.46] | 120.90 | 177.26 | 298.46 |

1.5 | [165.25, 103.03] | [247.76, 150.53] | [345.55, 255.18] | 103.03 | 150.53 | 255.18 |

1.6 | [158.07, 88.61] | [236.47, 129.01] | [332.90, 218.90] | 88.61 | 129.01 | 218.90 |

1.7 | [151.42, 76.92] | [226.14, 111.61] | [320.47, 189.04] | 76.92 | 111.61 | 189.04 |

1.8 | [145.30, 67.36] | [216.70, 97.42] | [308.54, 164.53] | 67.36 | 97.42 | 164.53 |

1.9 | [139.65, 59.47] | [208.06, 85.73] | [297.23, 144.29] | 59.47 | 85.73 | 144.29 |

2 | [134.44, 52.89] | [200.13, 76.01] | [286.60, 127.46] | 52.89 | 76.01 | 127.46 |

2.5 | [113.69, 32.17] | [168.76, 45.55] | [242.88, 75.01] | 32.17 | 45.55 | 75.01 |

3 | [99.01, 21.79] | [146.74, 30.45] | [211.32, 49.30] | 21.79 | 30.45 | 49.30 |

4 | [79.63, 12.21] | [117.73, 16.65] | [169.38, 26.17] | 12.21 | 16.65 | 26.17 |

5 | [67.30, 8.05] | [99.31, 10.76] | [142.69, 16.46] | 8.05 | 10.76 | 16.46 |

6 | [58.70, 5.87] | [86.47, 7.69] | [124.09, 11.50] | 5.87 | 7.69 | 11.50 |

Sample No. | ${\mathit{v}}_{\mathit{N}}$ | Sample No. | ${\mathit{v}}_{\mathit{N}}$ |
---|---|---|---|

1 | [3.01, 2.76] | 21 | [0.36, 16.32] |

2 | [2.61, 7.57] | 22 | [0.39, 4.44] |

3 | [7.74, 4.57] | 23 | [0.98, 10.49] |

4 | [0.84, 4.25] | 24 | [6.06, 6.49] |

5 | [1.19, 10.66] | 25 | [7.31, 2.59] |

6 | [2.55, 10.25] | 26 | [2.54, 9.34] |

7 | [3.73, 7.66] | 27 | [6.18, 11.58] |

8 | [3.37, 6.82] | 28 | [1.78, 6.91] |

9 | [6.19, 5.43] | 29 | [2.61, 7.28] |

10 | [6.12, 4.31] | 30 | [5.05, 4.73] |

11 | [3.03, 9.71] | 31 | [3.67, 8.89] |

12 | [0.33, 2.64] | 32 | [4.74, 6.45] |

13 | [3.46, 5.18] | 33 | [0.36, 13.32] |

14 | [3.11, 11.91] | 34 | [3.00, 9.29] |

15 | [1.67, 5.78] | 35 | [0.67, 11.71] |

16 | [1.09, 4.59] | 36 | [0.61, 3.30] |

17 | [2.29, 8.98] | 37 | [2.01, 1.69] |

18 | [2.47, 4.16] | 38 | [0.29, 15.05] |

19 | [1.22, 11.02] | 39 | [1.00, 12.85] |

20 | [3.13, 7.45] | 40 | [2.55, 9.40] |

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**MDPI and ACS Style**

Aslam, M.; Khan, N.; Albassam, M.
Control Chart for Failure-Censored Reliability Tests under Uncertainty Environment. *Symmetry* **2018**, *10*, 690.
https://doi.org/10.3390/sym10120690

**AMA Style**

Aslam M, Khan N, Albassam M.
Control Chart for Failure-Censored Reliability Tests under Uncertainty Environment. *Symmetry*. 2018; 10(12):690.
https://doi.org/10.3390/sym10120690

**Chicago/Turabian Style**

Aslam, Muhammad, Nasrullah Khan, and Mohammed Albassam.
2018. "Control Chart for Failure-Censored Reliability Tests under Uncertainty Environment" *Symmetry* 10, no. 12: 690.
https://doi.org/10.3390/sym10120690