Correction: In question 3 (b), 13:37 the standard deviation has to be 5.4 instead of 4.5. The rest of the working out is fine. Sorry for the inconvenience.
@@Anniekhan3446 Hi. Because we have to find the probability that exactly two of them will be moved. In this case, we just need any 2 of them. So, order doesn’t matter. That’s why we can use combination which is 4C2 (the number of ways to choose 2 items from 4 items without order)
I usually use it when the number of data is odd, but you can also use n/2 and round up the .5 to get the position of median. For instance, in this question, n=31. 31/2 = 15.5, then round it up to 16th which is the position of median
You are right. It has to be 5.4. I copied the wrong number from my notes while recording this video (from 5.4 to 4.5). Sorry about that. Anyway, the other parts are fine. Thanks for your help:)
Because the probability of two packages are delivered. So, we multiply the probability of each delivered package together, aka, square them. Same reason with the other two packages that won't be delivered by Jemima.
Correction: In question 3 (b), 13:37 the standard deviation has to be 5.4 instead of 4.5. The rest of the working out is fine. Sorry for the inconvenience.
For question 3 the last part why is it 4C2 I understand 4 because there are 4 boxes but what about 2 will it always be 2?
@@Anniekhan3446 Hi. Because we have to find the probability that exactly two of them will be moved. In this case, we just need any 2 of them. So, order doesn’t matter. That’s why we can use combination which is 4C2 (the number of ways to choose 2 items from 4 items without order)
thanks!
a queen
did we use n + 1 in q2 because we have even number of data?
I usually use it when the number of data is odd, but you can also use n/2 and round up the .5 to get the position of median. For instance, in this question, n=31. 31/2 = 15.5, then round it up to 16th which is the position of median
How is the standard deviation in question 3(b) 4.5?
You are right. It has to be 5.4. I copied the wrong number from my notes while recording this video (from 5.4 to 4.5). Sorry about that. Anyway, the other parts are fine. Thanks for your help:)
@@revisionmania7254 Oh I see, thank you for response!
Wow you have started youtube channel
Why didnt you use the percentage points of distribution table in question 3b
the z vlue for 15% is 1.0364 it gives the same answer but more accurate.
yeah i used that, but values would be around same, for probability of
For part 3c can't we just find the probability between 18 and 23.6?
Yes, in the video is how we find it. We subtract the left areas to find the area (probability) between w=18 and 23.6
@@revisionmania7254 but you also divided by 0.85, why is that?
@@7mood593 Conditional probability
@@revisionmania7254 why did you do that though? Why couldn’t we just subtract what is the difference
Question why didn’t you use the second table in 3b ?
Thank you miss for the help
You are welcome! 😊
Can you please do s2 jan 2021
Sure😊
Thanks a lot sister!!!
My pleasure :)
This is extremely helpful thank you
well explained i got to understand everything thanks 😁😁😍
Thank you! Glad it helped😊 Part 2 has been uploaded. Hope you like it!
Miss, why did you at 20:19 square the numbers?
Because the probability of two packages are delivered. So, we multiply the probability of each delivered package together, aka, square them. Same reason with the other two packages that won't be delivered by Jemima.
Hello, can you please send me a link to the mark scheme PDF of this paper?
They made the paper crazy hard compared to previous syllabus
This is extremely helpful and all, but I'm just super curious why do you sound like AI robot 😅😅😅
Nervousness, love. I'll try to sound more natural in the next video :-)
Hello sir Please do S1of Oct 2020 within 19th of april..😢😢
HI. Not sure cuz there're so many papers in the list that haven't been done. Will add this to the list. Sorry for the inconvenience
Great video!
I can’t find this paper online in pdf is there any way you can give it to me? Great video 👍
Give me ur email or something, i can send it to u
@@studyt-t4772 Please send it to me
Can I have the Link to the PDF of the Past Paper for the Month of Jan 2021?
do you still want it? i have it if u need
@@mohammadrabialmahmoud6486 Please send it to me
Wow👏🏾👏🏾 thank you so much for this 🥰
You are welcome :)
Very well explained teacher.. 🙌🙌🙌
Thanks😁