# S1 Normal DistributionWatch

Announcements
This discussion is closed.
Thread starter 14 years ago
#1
In an experiment the length of a bar is measured many times...normal distribution with mean 1.34 and SD 0.02. Find the prob than any one measured value a) exceeds 1.37 b)is between 1.31 and 1.37 c)is between 1.33 and 1.39 d)find the length h for which the prob that any one measured value is less than h is 0.1.
Thanks in advance to anyone who can do them. I've done abc and just want to check answers but am stuck on d.
0
Thread starter 14 years ago
#2
0
Thread starter 14 years ago
#3
0
14 years ago
#4
(Original post by tango1)
In an experiment the length of a bar is measured many times...normal distribution with mean 1.34 and SD 0.02. Find the prob than any one measured value a) exceeds 1.37 b)is between 1.31 and 1.37 c)is between 1.33 and 1.39 d)find the length h for which the prob that any one measured value is less than h is 0.1.
Thanks in advance to anyone who can do them. I've done abc and just want to check answers but am stuck on d.

a) z = ( 1.37 - 1.34 ) / 0.02 = 1.5

P = 1 - Phi(1.5) = 1 - 0.9332 = 0.0668

b) Phi (2) - Phi (-2) = Phi (2) - (1-(Phi(2))) = 0.9554

c) Phi (2.5) - Phi (-0.5) = 0.9938 - (1-Phi(0.5)) = 0.9938 - 0.3085 = 0.6853

d) z = x - (x-bar) / SD
Phi^-1 (0.1) = - Phi^-1 (0.1) = -1.2816

=> -1.2816 = ( x - 1.34 ) / 0.02
= -0.025632 = x - 1.34
= 1.314368 = x

Length = 1.314368 units.
0
Thread starter 14 years ago
#5
thx v.much. good luck on your path towards fame and fortune.(i'm a part time psychic)
0
X
new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### University open days

• Bournemouth University
Midwifery Open Day at Portsmouth Campus Undergraduate
Wed, 16 Oct '19
• Teesside University
All faculties open Undergraduate
Wed, 16 Oct '19
• University of the Arts London
London College of Fashion – Cordwainers Footwear and Bags & Accessories Undergraduate
Wed, 16 Oct '19

### Poll

Join the discussion

#### How has the start of this academic year been for you?

Loving it - gonna be a great year (138)
17.72%
It's just nice to be back! (210)
26.96%
Not great so far... (280)
35.94%
I want to drop out! (151)
19.38%