10.5 quantitative investigations of variation

Question 1

What is interspecific variation?

Answer 1

Variation between all living things

Question 2

What is intraspecific variation?

Answer 2

variation within a species

Question 3

What is sampling?

Answer 3

Taking measurements of individuals selected from a population which is being investigated which will represent the entire population

Question 4

Why might sampling not be representative?

Answer 4

• sampling bias: selectors might make unrepresentative choices (knowingly or unknowingly)
• chance: by coincidence the samples may not be representative

Question 5

How can you avoid sampling bias?

Answer 5

by random sampling;

1) divide each area into a grid of numbered lines
2) using randomly generated numbers, obtain coordinates
3) take samples at the intersection of the coordinates

Question 6

How can you minimise the effect of chance?

Answer 6

• Use a large sample size: more individuals means that chance is less likely to effect the result and anomolies have less influence.
• Analyse data collected: statistical tests can determine the extent to which chance influenced the data

Question 7

Describe a normal distribution curve.

Answer 7

the mean, mode and median all have the same value.

Question 8

Describe a skewed distribution curve.

Answer 8

the mean, mode and median all have different values.

Question 9

What is the mean of a graph?

Answer 9

the measurement at the maximum height of a curve.

Question 10

What is standard deviation on a graph?

Answer 10

The width of a curve, it shows the range of values around the mean.
Can be calculated, check textbook for equation.