What does NULL HYPOTHESIS mean?! :/

Announcements Posted on
Four hours left to win £100 of Amazon vouchers!! Don't miss out! Take our short survey to enter 24-10-2016
1. A student observed that the yield of oranges increased as the abundance of honeybee hives in the orange hives increased. She counted the number of hives in different groves and then measured the yield in each grove. She decided to determine whether there was any association between the two variables.

Grove no |No. of honeybee hives/ grove |Yield of Oranges in tonnes/ grove
1 | 122 | 107
2 | 66 | 32
3 | 79 | 61
4 | 94 | 111
5 | 43 | 48
6 | 64 | 72
7 | 30 | 34
8 | 91 | 76
9 | 110 | 119
10 | 76 | 90
11 | 61 | 90
12 | 104 | 59
13 | 67 | 64
14 | 30 | 46
15 | 92 | 90

So I used the Correlation coefficient to get the calculated value which is 0.68125. and the critical value is 0.5385.

Now the question says:
State a suitable null hypothesis for this investigation.
2. The null hypothesis is a statement where you'd say there will be no relationship between the two variables and any changes would be due to chance.
So, There will be no affect of the number of honey bees on the yield of oranges, any change in this yield will be due to chance
You'd only accept this hypothesis if the result was insignificant xx
3. The null hypothesis is what you are trying to disprove, so as the poster above says, in your case, no relationship.
4. Ho : there is no correlation between hive numbers & orange yield
5. (Original post by satanslilsis)
The null hypothesis is a statement where you'd say there will be no relationship between the two variables and any changes would be due to chance.
So, There will be no affect of the number of honey bees on the yield of oranges, any change in this yield will be due to chance
You'd only accept this hypothesis if the result was insignificant xx
(Original post by cheshiremum)
The null hypothesis is what you are trying to disprove, so as the poster above says, in your case, no relationship.
(Original post by the bear)
Ho : there is no correlation between hive numbers & orange yield
Oh, I see! Cheers!!
6. So one more thing, if the null hypothesis means that there will be no relationship between the two variables, how can it also mean that there's no significant difference between two variables ?
Spoiler:
Show
7. BUMP..
BUMP..
General forum etiquette is not to bump unless it's past one day.

As for your question, generally if there is no relationship, there will be no significant difference between variables.

Here's an example:
There's a jar filled with black and white marbles in an equal proportion. You are calculating the probability of picking out a white marble when using a right hand versus the probability of picking out a marble with a left hand.

Since there already is a 50% probability of picking a white marble, there should be no difference between using a right hand or left hand with a high sample volume.

[EDIT] If there was a relationship between the two, there should be a significant difference.

An example of this would be a colour change reaction between 2 compounds. If compound 2 is the limiting factor, there should be a degree of colour change dependent upon the concentration of compound 2. Thus, a significant difference. However, if Compound 2 does not react with Compound 1, there is no reaction, thus a value of 0 for colour change.
So one more thing, if the null hypothesis means that there will be no relationship between the two variables, how can it also mean that there's no significant difference between two variables ?
Spoiler:
Show
Those two statements are different. Usually if you're testing a hypothesis you are either looking for a relationship between two variables or you can be looking for a significant difference between two variables. Depending on which one your main hypothesis is, the other one respectively will be the null hypothesis.

No relationship between two variables is not the same as there being no significant difference between two variables. You will have to choose your null hypothesis carefully, making sure it counters your main hypothesis.
10. (Original post by zombiejon)
General forum etiquette is not to bump unless it's past one day.

As for your question, generally if there is no relationship, there will be no significant difference between variables.

Here's an example:
There's a jar filled with black and white marbles in an equal proportion. You are calculating the probability of picking out a white marble when using a right hand versus the probability of picking out a marble with a left hand.

Since there already is a 50% probability of picking a white marble, there should be no difference between using a right hand or left hand with a high sample volume.

[EDIT] If there was a relationship between the two, there should be a significant difference.

An example of this would be a colour change reaction between 2 compounds. If compound 2 is the limiting factor, there should be a degree of colour change dependent upon the concentration of compound 2. Thus, a significant difference. However, if Compound 2 does not react with Compound 1, there is no reaction, thus a value of 0 for colour change.
Those two statements are different. Usually if you're testing a hypothesis you are either looking for a relationship between two variables or you can be looking for a significant difference between two variables. Depending on which one your main hypothesis is, the other one respectively will be the null hypothesis.

No relationship between two variables is not the same as there being no significant difference between two variables. You will have to choose your null hypothesis carefully, making sure it counters your main hypothesis.
I see!! Thanks a lot!!

Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: April 16, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

Who is getting a uni offer this half term?

Find out which unis are hot off the mark here

How to get a 1st class degree

Poll
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.