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junior college 1 | H1 Maths
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Chowder
Chowder

junior college 1 chevron_right H1 Maths

Help pls

Date Posted: 6 years ago
Views: 818

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Jiayang
Jiayang's answer
1883 answers (Tutor Details)
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Chowder
Chowder
6 years ago
How do u get the -1.0364
Jiayang
Jiayang
6 years ago
I used the calc. There’s an inverse normal dist. function.

You can use the table also but since theres no 0.85 in the table you'll have to do a lil bit of interpolation. Even then your answer won't be as exact as the one obtained from the calc.
Chowder
Chowder
6 years ago
Wait but how did u do that?
Chowder
Chowder
6 years ago
What did u type in the calc?
Jiayang
Jiayang
6 years ago
Go to the invNorm function...

Area: 0.15
μ: 0
σ: 1
Chowder
Chowder
6 years ago
Is there another way other than using the calc? Bcos i dont think im using the calc ure talking abt
Jiayang
Jiayang
6 years ago
TI-84?
Chowder
Chowder
6 years ago
If i use the table i got 0.1977? Not the same as urs?
Im using fx-96sg
Jiayang
Jiayang
6 years ago
If not you can use Microsoft Excel

=NORM.INV(0.15,0,1)
Jiayang
Jiayang
6 years ago
You can't do all this with that calculator HAHAHA

Didn't your lecturer tell yall to invest in a GC?
Chowder
Chowder
6 years ago
Wait but help me first. I wanna know if i were to use the graph and z table only to solve. Bcos my tcr didnt tell me abt buying those type of calc? How do u use the z table and do the interpolation. Can show me the working pls
Jiayang
Jiayang
6 years ago
How did you get 0.1977?
Chowder
Chowder
6 years ago
I take 0.8 from the left column and 0.05 on the top column and they intersect at that point?
Jiayang
Jiayang
6 years ago
Go see what I’ve just uploaded
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Jiayang
Jiayang's answer
1883 answers (Tutor Details)
Chowder
Chowder
6 years ago
Omg sorry i forget to tell you that im using the right tail z table. The neg one i havent learn yet. If ure free can u help me explain using the right tail table pls pls pls
Jiayang
Jiayang
6 years ago
So apparently for right tailed it's pretty much the same. Instead of looking at eg. p(x<10) it's now p(x>10).

So our Qn the arrow was < to use the right tailed you need to do the 1 minus to change the arrow to >

So you'll end up with 1-0.15= 0.85

But now your table doesn't have values >0.5 cus it's right tailed you have to look at 1-0.85 which is 0.15
Then you do the same o interpolation and take the negative
Chowder
Chowder
6 years ago
Yup. But 1-0.15 i got 0.85. And the probability for 0.85 is 0.1997. And i didnt get the exact same ans as yours?
Jiayang
Jiayang
6 years ago
You're reading the values wrongly. See how I got 1.03 and 1.04

The numbers on the borders are Nott he probability density, they are the z values

The values inside are the probability density values, look for 0.15 there
Jiayang
Jiayang
6 years ago
Which you won't be able to find cus they only give 0.1515 and 0.1492. that's when you should interpolate between these two values to get the corresponding z value
Chowder
Chowder
6 years ago
Wait omg means i read wrongly all this while? But i thought 0.15 is the z value? Ok sorry but last Q how do u know if the Q is referring to the z value or the probability? They didnt state that the 15℅ is the probability or the z value. How to know
Jiayang
Jiayang
6 years ago
The Q said 15% of the jumps so it means 15% of the time he jumps below 5m. So statistically speaking, the next time he jumps we can say he got 15% probability of jumping lower than 5m

Which course are you in btw. I'm curious
Chowder
Chowder
6 years ago
The question doesnt really always tell the z value? Is it correct if i say if theyre using perventage its always probability and not z value? Im taking chemical engineering course
Jiayang
Jiayang
6 years ago
Of all the qns I've encountered they won't tell me the z value. Most won't tell me I have to standardise first either. I guess if you have missing mean and/or SD then you'll have to use the standard z table. Cus calcs need the mean and SD for calculations.
Chowder
Chowder
6 years ago
Oh okok thank you
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Jiayang
Jiayang's answer
1883 answers (Tutor Details)
Circle: probability
Underlined: z value (column+row ie 1.0+0.04=1.04)
Chowder
Chowder
6 years ago
Oh wow ok ive been reading it wrong fml. Thank you for your help really
Jiayang
Jiayang
6 years ago
When you read it your way, didn't you find it odd that you can have probability larger than 1? Haha
Chowder
Chowder
6 years ago
Nvr think of that before. I just go straight to solving the Qs and i thought probability can be more than 1 de
Jiayang
Jiayang
6 years ago
:o probability of 1 means event confirm die die must occur. Then more than 1 means what? There's nothing in our universe that's more likely than something that is definite.
Chowder
Chowder
6 years ago
Walao i feel so stupid now leh
Jiayang
Jiayang
6 years ago
It's okay... I feel stupid all the time also :)
Chowder
Chowder
6 years ago
Can help me with principles of inorgsnic chem pls pls