4B- Investigating Variation Flashcards
What is variation?
Variation is the differences that exists between variables.
There are variations between species as well as within them.
Variation can be caused by genetic factors
Different species have different genes which cause variations between species.
Variation within species is caused by…
Individuals of the same species have the same genes but different alleles, leading to variation.
It can also be caused by differences within the environment. Most variation within a species is a combination between both.
Eg Your DNA may code to be 6’0 but if you don’t eat enough you’ll only ever grow to 5’2.
Why do you only use a sample to study variation?
You only look at a sample as it would be both time consuming and nearly impossible to catch all the individuals of a group.
Why do samples have to be random?
To make sure the sample isn’t bis and it’s representative of the population so conclusions can be drawn.
Also to ensure that any variation seen isn’t due to chance. You would use a statistical test to analyse the results to see if you can reject the null hypothesis.
What does standard deviation tell you about a sample?
It tells you how much the values in a single sample vary.
It’s a spread of the values around a mean.
