Maths Statistics Question

Watch this thread
CODvenom
Badges: 5
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 1 year ago
#1
A machine puts crisps into packets.
The weight of crisps in each packet, M grams follows a normal distribution with mean 40 g

Given that 20% of packets contain more than 42 g of crisps,

(a) Find, to 2dp, the value of k such that P(k < A < 40) = 0.40


Eighteen packets of crisps are selected at random.
(b) Find the probability that fewer than 3 of these packets contain more than 42 g or crisps.


A second machine makes larger packets of crisps of weight Y grams, where Y is normally distributed with standard deviation 7.5 g

A manager believes that the mean weight of crisps put into each packet is greater than 175 g

A random sample of 10 packets from this second machine was found to have a mean weight of crisps of 178.5 g

(c) Test whether or not the mean weight of crisps in larger packets, filled by the second machine, is greater than 175 g
State your hypotheses clearly and use a 5% level of significance.
0
reply
RLH17
Badges: 7
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report 1 year ago
#2
To start you need to find the standard deviation by using "Given that 20% of packets contain more than 42 g of crisps" in standard normal distribution.
You are then able to do part a with the mean and standard deviation you have worked out.
Part c is hypothesis tests
Last edited by RLH17; 1 year ago
0
reply
the bear
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report 1 year ago
#3
part b : use the binomial distribution
0
reply
kimw0001
Badges: 4
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report 1 year ago
#4
(Original post by the bear)
part b : use the binomial distribution
what would you need to put in as p, x and n?
0
reply
the bear
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#5
Report 1 year ago
#5
(Original post by kimw0001)
what would you need to put in as p, x and n?
what would you suggest ?

:holmes:
0
reply
kimw0001
Badges: 4
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#6
Report 1 year ago
#6
(Original post by the bear)
what would you suggest ?

:holmes:
n =18 , not sure about p or x
0
reply
the bear
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#7
Report 1 year ago
#7
(Original post by kimw0001)
n =18 , not sure about p or x
n is good.

for p you are looking for a suitable probability of one success. then you need to apply that for x successes.
0
reply
kimw0001
Badges: 4
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#8
Report 1 year ago
#8
(Original post by the bear)
n is good.

for p you are looking for a suitable probability of one success. then you need to apply that for x successes.
how do i find p?
0
reply
the bear
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#9
Report 1 year ago
#9
(Original post by kimw0001)
how do i find p?
just read through the first part of the question.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

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

Personalise

Y13's - If you haven't confirmed your firm and insurance choices yet, why is that?

I am waiting until the deadline in case anything in my life changes (8)
22.86%
I am waiting until the deadline in case something else changes (e.g. exams/pandemic related concerns) (3)
8.57%
I am waiting until I can see the unis in person (4)
11.43%
I still have more questions before I make my decision (3)
8.57%
No reason, just haven't entered it yet (8)
22.86%
Something else (let us know in the thread!) (9)
25.71%

Watched Threads

View All