S
signorasera
Guest
(slight changes in values have been made from the similar question in the textbook, so you are assured that I am only trying to understand the material)
A sample of 10 readings of shoe sales gave:
expected mean = 90; standard deviation = 3;
Suppose that specifications call for a population standard deviation of at most 4.
Using a 5% level of significance, test the hypothesis that the specification is satisfied.
The use of statistical softwares is allowed.
I use Minitab software, but I am not sure if 1-Variance test is the appropriate test because it only needs Sample Size, Sample Standard Deviation, and Hypothesized Standard Deviation and doesn't care what the Sample Mean is, but the question gives Expected Mean = 90 it has to be there for a reason don't you think?
Any help is appreciated. Thank you in advance.
actually we suppose that the specifications call for a population standard deviation of at most 2 (because, before I supposed that the population Standard Deviation was MORE than the given Sample Standard Deviation of 3, which was plain dumb, the Null Hypothesis (sigma < 4) would definitely be favoured without any needs for a calculation...sorry about that)
I thought about assuming the population distribution to be Normal ~N(90,3^2) then scaling it down to Mean=0: Z=(X-90) ~N(0,3^2/10) and then perform the Chisquare test by doing 1-Variance test in Minitab, but what difference would it make? since the Range of Standard Deviation would be the same whether Mean is scaled to 0 or not.
So does this mean that the given value of Sample Mean = 90 would do nothing, and can be ignored in this question?
A sample of 10 readings of shoe sales gave:
expected mean = 90; standard deviation = 3;
Suppose that specifications call for a population standard deviation of at most 4.
Using a 5% level of significance, test the hypothesis that the specification is satisfied.
The use of statistical softwares is allowed.
I use Minitab software, but I am not sure if 1-Variance test is the appropriate test because it only needs Sample Size, Sample Standard Deviation, and Hypothesized Standard Deviation and doesn't care what the Sample Mean is, but the question gives Expected Mean = 90 it has to be there for a reason don't you think?
Any help is appreciated. Thank you in advance.
actually we suppose that the specifications call for a population standard deviation of at most 2 (because, before I supposed that the population Standard Deviation was MORE than the given Sample Standard Deviation of 3, which was plain dumb, the Null Hypothesis (sigma < 4) would definitely be favoured without any needs for a calculation...sorry about that)
I thought about assuming the population distribution to be Normal ~N(90,3^2) then scaling it down to Mean=0: Z=(X-90) ~N(0,3^2/10) and then perform the Chisquare test by doing 1-Variance test in Minitab, but what difference would it make? since the Range of Standard Deviation would be the same whether Mean is scaled to 0 or not.
So does this mean that the given value of Sample Mean = 90 would do nothing, and can be ignored in this question?