Question

help with part b

Answer 1

@Haseeb96 do you know how to work this?

Answer 2

sorry, i forgot probability

Answer 3

thank you for looking though

Answer 4

It's hypothesis testing isn't it?

Answer 5

\(T = \frac{\bar X - 47,000}{4000/\sqrt{120} }\) is supposed to have \(\norm (0,1)\) distribution.
It should not be far away from 0.
But here, \(\bar X = 46,500\). What is the value of \(T\)?

Answer 6

I dont know what the value of T is

Answer 7

\(\frac{46500 - 47000}{4000/\sqrt{120}}\)

Answer 8

Is this value "ok" for a normal(0,1) distribution?

Answer 9

i think the answer is 0.45

Answer 10

@reemii what are you thinking

Answer 11

I find -1.37

Answer 12

can you show me how to go to this answer step by step?

Answer 13

\(T = \frac{\bar X - \mu}{\sigma/\sqrt n} = \frac{46500 - 47000}{4000/\sqrt{120}} = -1.37\)

Answer 14

ok i see, i dont understand though... how i put this sort of work into staticial justification reasoing with words

Answer 15

The value is -1.37, right?

Now, after translating and scaling, we can see that the situation {46500,47000,120,4000} is similar to a centered one:{ T, 0, 120, 1}. This is the scaling trick.
The question is: is T=-1.37 a value that's surprising or not surprising for a normal(0,1) distribution?

Answer 16

When you check in the z-scores table of the N(0,1) distribution, you see that P(N<-1.37) is small.. like smaller than a few %. . . that means this value is surprising.