Tham khảo tài liệu 'product and process comparisons_7', kỹ thuật - công nghệ, điện - điện tử phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . Comparisons based on data from two processes ENGINEERING STATISTICS HANDBOOK hW tools raids lỉEÂtCH BACK Nixf 7. Product and Process Comparisons . Comparisons based on data from two processes Outline for In many manufacturing environments it is common to have two or more this section processes performing the same task or generating similar products. The following pages describe tests covering several of the most common and useful cases for two processes. 1. Do two processes have the same mean 1. Tests when the standard deviations are equal 2. Tests when the standard deviations are unequal 3. Tests for paired data 2. Do two processes have the same standard deviation 3. Do two processes produce the same proportion of defectives 4. If the observations are failure times are the failure rates or mean times to failure the same Example of a dual track process For example in an automobile manufacturing plant there may exist several assembly lines producing the same part. If one line goes down for some reason parts can still be produced and production will not be stopped. For example if the parts are piston rings for a particular model car the rings produced by either line should conform to a given set of specifications. How does one confirm that the two processes are in fact producing rings that are similar That is how does one determine if the two processes are similar http div898 handbook prc section3 1 of 2 5 1 2006 10 38 47 AM . Comparisons based on data from two processes The goal is In order to answer this question data on piston rings are collected for to determine each process. For example on a particular day data on the diameters of if the two ten piston rings from each process are measured over a one-hour time processes frame. are similar To determine if the two processes are similar we are interested in answering the following questions 1. Do the two processes produce piston rings with the same diameter 2. Do the two .
