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Statistical techniques

IIzabel6y ago
Hi John, If mean is 150 standard deviation is 20 how to find z score without value of x .. Answer says it's .84
John MoffatJohn MoffatTutor6y ago#1
Please do check that you have typed out. the whole of the question correctly because on what you have typed it is not possible. If it is from the BPP Revision Kit then please tell me which question and then I can check for myself :-)
IIzabel6y ago#2
Apologies John. Its 4b 19
IIzabel6y ago#3
Also John , i am seeing so mnay times in bpp about calculating z score of upper quartile .. upper quartile is 25% . everywhere they say from the table the z score us 0.67 i cant get my head around it
John MoffatJohn MoffatTutor6y ago#4
I am now away from home until late tomorrow night and do not have the Revision Kit with me. Please ask again on Tuesday and I will answer you then.
IIzabel6y ago#5
Hi John, Q 4b19 from BPP Also 4b18 , where they are asking about upperquartile. In a normal distribution of the upper quartile 3rd or 4th ? I don’t also understand how they decided there are 0.67 standard deviations
BBrahmjot6y ago#6
hey! I have just started preparing for acca nd beginning with f1. So can you tell me that the notes from opentution are sufficient for the exam purpose ? Also can you describe how the initial exams are(difficulty level)
John MoffatJohn MoffatTutor6y ago#7
brahmjot12: Paper F1 is now called Paper AB, so please do not keep posting the same question in irrelevant forums - either ask in the general ACCA forum or in the Paper AB forum.
John MoffatJohn MoffatTutor6y ago#8
Q 4b.19 is not as you originally typed it!!! 50% of the distribution is below the mean, therefore there must be 30% between the mean and the limit that we are after. So you need to work backwards in the tables (as I show in my lectures) to find what z-score gives an answer of 0.30. The closest is a z-score of 0.84 (which gives a probability of 0.2995)
John MoffatJohn MoffatTutor6y ago#9
Q4b 18 The upper quartile is the top 25%, so the limit required is the figure for which 75% of the observations lie below. It is then the same workings as for 4b19, except that it is 75% and not 80%.
IIzabel6y ago#10
Thank you very very much. You are a
John MoffatJohn MoffatTutor6y ago#11
You are welcome :-)
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