Reliability Reliability is the likelihood that an object will perform its function or a process will yield satisfactory results. Often,the reliability of system must be predicted from an estimate of the reliability of its components. Shanghai Jiao Tong University 6
Shanghai Jiao Tong University 6 Reliability n Reliability is the likelihood that an object will perform its function or a process will yield satisfactory results. n Often, the reliability of system must be predicted from an estimate of the reliability of its components
Statistical Process Control Statistical Process Control is used to monitor processes in a way such that normal variability of the operation is accounted for, but long term degradation is observed. The process is sampled at given intervals and the statistics of the samples compared.The cost of the inspection must be balanced versus the dangers of either missing a change in the process or misinterpreting a statistical fluctuation for a change in the process. Shanghai Jiao Tong University 7
Shanghai Jiao Tong University 7 Statistical Process Control n Statistical Process Control is used to monitor processes in a way such that normal variability of the operation is accounted for, but long term degradation is observed. n The process is sampled at given intervals and the statistics of the samples compared. The cost of the inspection must be balanced versus the dangers of either missing a change in the process or misinterpreting a statistical fluctuation for a change in the process
Regression Regression allows us to determine a relationship between two or more variables,even when there is uncertainly in the measurements and the relationship may not be immediately obvious. We will use regression to establish the Taylor's Tool Life Equation. Shanghai Jiao Tong University 8
Shanghai Jiao Tong University 8 Regression n Regression allows us to determine a relationship between two or more variables, even when there is uncertainly in the measurements and the relationship may not be immediately obvious. n We will use regression to establish the Taylor’s Tool Life Equation
Terminology If the parameters of a model of a system or a process are known,given,or established from past history,then we have a probability problem and we can deduce the behavior of the system from the model.However,if the parameters are unknown and have to be estimated from the available data,then we have a statistical problem. Shanghai Jiao Tong University 9
Shanghai Jiao Tong University 9 Terminology n If the parameters of a model of a system or a process are known, given, or established from past history, then we have a probability problem and we can deduce the behavior of the system from the model. However, if the parameters are unknown and have to be estimated from the available data, then we have a statistical problem
Representing Statistical Data ■Histogram Group the data into bins or intervals and show the size of each bin (interval)graphically. Cumulative distribution Show graphically how much of the data is below a given value Shanghai Jiao Tong University 10
Shanghai Jiao Tong University 10 Representing Statistical Data n Histogram Group n the data into bins or intervals and show the size of each bin (interval) graphically. n Cumulative distribution n Show graphically how much of the data is below a given value