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Stage 4: Data analysis

Annotate maps and sketches to identify evidence of wave-cut platforms, wave-cut notches and slumping. Most of your analysis will be to summarise the major findings of the field investigations, but it may be possible to carry out some statistical analysis.

Worked example

This is an investigation into whether there is a link between cliff gradient and the presence of a beach. It can be tested using the Mann-Whitney U Test. Need more information about this test?

The null hypothesis is that there is no significant difference in the two medians.

The results were collected and summarised as follows.

Gradient (degrees)
No beach	Beach
20	15
35	21
32	36
16	12
41	10

Give each result a rank.

No beach		Beach
gradient	rank	gradient	rank
20	5	15	3
35	8	21	6
32	7	36	9
16	4	12	2
41	10	10	1
total =	34	total =	21

Now calculate U1 and U2. In this example, U1 = 19 and U2 = 6. Choose the smaller of the two values (i.e. 6).

The critical value at p=0.05 probability level is 2. Since our calculated value of 6 is < 2, the null hypothesis is not rejected.

In conclusion, there is not a significant difference between the teo medians, and therefore in cliff gradient between places with a beach and places without a beach. Some other factors must be imporatnt here.

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