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Exam Hack | CIE A2 Maths | S2 | Sampling & Estimation Question

🕑 Added 2022-11-07 02:38:24 +0000 UTC

Comments

abcdefg

For Question 12 why do you not use the true value of the population variance to calculate the confidence interval?

Adetona Adegbite

Okay thanks

Intuitive

Because that's the actual standard deviation, why would I need to estimate the standard deviation if they just give it to me?

Adetona Adegbite

please in the second question, why did you use the population standard deviation and not find an estimate to calculate the confidence interval

Umanga Regmi

just look below the table in the data booklet, there are critical values where you can find some of the commonly used inverse values

Eirene Chiam

oh, using a calculator, you have to press, menu + 7 and then press 3 for Inverse Normal function, make sure when you are entering your values, that Area = z value (e.g 0.995), σ = 1, µ = 0, the actual CI value for 99% is actually = 2.576, but i'm not exactly sure how he gets 2.574 but I checked online and its 2.576

Rajdip Shah

Hey! great video. Thanks! A question; when I put 0.995 as x in my calculator(fx-991EX) for Normal PD, I get an answer of 0.243180... whereas you get an answer of 2.574 on the video at 16:10. Why might that be?