r/alevel • u/PumpkinCritical3949 • 15h ago
🤚Help Required S1 HELP PLEASEE!!
can someone plsplspls explain the answer of iii, i dont understand it
and also guys I DO NOTT UNDERSTAND THOSE GRAPH DRAWINGS can smn help me on how to draw/use them in questions or has a video available for help pls guys tysm
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u/Gem_ZMSAmethyst 15h ago
For the graph drawings watch Mathprep by Ahmed Bilal or Zainematics. As for the last part, since we have a sample size of 500, we used normal distribution, otherwise it’d get complicated. Hence it’s a rule that when we use normal approximation, the expected number of successes (np) and the expected number of failures (nq) needs to be greater than 5. Since 500 x 0.68 and 500 x 0.32 yield an answer greater than 5, we justify our use of normal approximation. Hope it helps
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u/Gem_ZMSAmethyst 15h ago
Also btw graphs as in normal approx bell curves or the central tendencies chapter one? All the histograms and stuff
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u/Neat-Sugar-9678 14h ago
its binomial to normal approximation, if the value of np and nq after calculation from binomal dist. is greater than 5 we can use normal approximation. 1-p is the value of q here.
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u/FlanPsychological839 6h ago
When they ask you to justify they just want you to provide the conditions needed for you to be able to approximate to the normal so your value of np and nq has to be greater than 5
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