Help needed! tough 9709 S1 problem!

[Mayisha M]

Can anyone help me with this sum, please? It's from o/n/09-62. I attached the mark scheme for your convenience Please help with number (ii)

 

[Zash Riyash]

How did they get z value without any calculation?

 

[tiki-taka]

Can anyone help me with this sum, please? It's from o/n/09-62. I attached the mark scheme for your convenience Please help with number (ii)
View attachment 52749 View attachment 52748

for normal distribution Q1 & Q3 are Always 25% & 75% so Z=+-0.674