Test of hypothesis in normal distribution but standard "

Here I am giving a screen shot of a solved example of a hypothesis test using "z" test statistic. I am puzzled at this question as there is no "n" given in this example. I hadn't encounter this type of question where we have to solve test of hypothesis question by using z-test but without mentioning "n" value.Here I am not talking about Normal distribution as an approximation of binomial or Poisson distribution
My main question is , where I can find these type of questions.
Please Guide me. image-21c864ab-a92d-44be-bf6d-320777146787609966262-compressed.jpg.jpeg

image-21c864ab-a92d-44be-bf6d-320777146787609966262-compressed.jpg.jpeg

Reply 1

old_engineer

11

Original post by alevelmath1

Here I am giving a screen shot of a solved example of a hypothesis test using "z" test statistic. I am puzzled at this question as there is no "n" given in this example. I hadn't encounter this type of question where we have to solve test of hypothesis question by using z-test but without mentioning "n" value.Here I am not talking about Normal distribution as an approximation of binomial or Poisson distribution
My main question is , where I can find these type of questions.
Please Guide me.

All normal distributions X~N(a, b^2) can be considered as linear transformations of the standard normal distribution Z~N(0, 1^2). Conversely, any normal distribution X~N(a, b^2) can be linearly transformed to Z~N(0, 1^2). There is no "n" factor involved in the transformation. Transforming normal distributions to standard normal form used to be much more important when the primary source of values for P(Z <= z) was a look-up table. Many problems can now be solved more directly via calculator, but there are still some advantages of working in terms of Z including (a) it can be easier for both student and examiner to see what's going on with a solution, and (b) certain critical values of Z, e.g. Z= +/-1.96 for 2.5% tails, tend to stick in the mind.

You should check past paper marking guides for your examining board to see what is expected in whichever exams you are taking.

Reply 2

alevelmath1

OP

9

well,I searched 20 years past papers of Edexcel,OCR,CIE.That's why I am perplexed as how to use test of hypothesis in simple normal distribution without "n" value.I have not find any material on those kind of Questions.I am looking for some stuff on this topic.

Reply 3

old_engineer

11

Original post by alevelmath1

well,I searched 20 years past papers of Edexcel,OCR,CIE.That's why I am perplexed as how to use test of hypothesis in simple normal distribution without "n" value.I have not find any material on those kind of Questions.I am looking for some stuff on this topic.