I
Inspector-71
My question surrounds tests on proportions so looking at Binomial for 1 and 2 proportion tests and chi-sq test for 3+ proportions
Am I correct in saying that these tests are only used to infer the proportions (and differences between them) of populations based on a sample?
So to take minitab?s example, a manager of three customer support centres want to check successful resolution (yes/no) for three different support centres so tallies successful and unsuccessful resolutions per branch in a table
If the manager tallies the yes/no per branch for all the calls and they come out %Yes 34, 35, 36, then surely they are different and we don?t need to run any stats tests?
Or
Are we saying that we do need a stats test because although we have all the calls to date, it is just a sample of the future population (assuming no changes)?
I am preparing training material on this and can imagine this being a tough sell.
Obviously it becomes simpler if we are sampling say 10 bolts per hour out of hundreds per production line and testing them to infer %defective of all the bolts.
Thanks,
Am I correct in saying that these tests are only used to infer the proportions (and differences between them) of populations based on a sample?
So to take minitab?s example, a manager of three customer support centres want to check successful resolution (yes/no) for three different support centres so tallies successful and unsuccessful resolutions per branch in a table
If the manager tallies the yes/no per branch for all the calls and they come out %Yes 34, 35, 36, then surely they are different and we don?t need to run any stats tests?
Or
Are we saying that we do need a stats test because although we have all the calls to date, it is just a sample of the future population (assuming no changes)?
I am preparing training material on this and can imagine this being a tough sell.
Obviously it becomes simpler if we are sampling say 10 bolts per hour out of hundreds per production line and testing them to infer %defective of all the bolts.
Thanks,