Study Figure 1a in the Resource Booklet and Figure 1b below.
Figure 1a
Tectonic setting of New Zealand
This data in Figure 1b was collected to investigate whether there was a significant difference in earthquake depth at the two plate boundaries shown in Figure 1a.
| Number of earthquakes recorded in 2016 | Mean focal depth of earthquakes (in kilometres) |
Plate boundary A | 186 | 34.8 |
Plate boundary B | 145 | 12.7 |
Figure 1b
Frequency and focal depth of earthquakes in New Zealand, 2016
i)
Calculate the average monthly frequency of earthquakes at the two plate boundaries.
You must show your working.
(2)
ii)
A Student’s t-test was used to determine whether there was a statistical difference in the mean focal depth of the earthquakes at the two plate boundaries.
Two hypotheses were tested:
Null Hypothesis: There is no statistically significant difference between the mean focal depth of earthquakes at the two plate boundaries. |
Alternative Hypothesis: There is a statistically significant difference between the mean focal depth of earthquakes at the two plate boundaries. |
Using the partially completed Student’s t-test below, calculate the value of t.
t =.....................................
(1)
iii)
Study Figure 1c below.
Confidence level | 0.10 (90% significance) | 0.05 (95% significance) | 0.01 (99% significance) |
Critical value of Student’s t-test | 1.6 | 2.0 | 2.6 |
Figure 1c
Critical values for this Student’s t-test
Using the Student’s t-test value calculated in (a) (ii), state whether there is a significant difference between the mean focal depth of the earthquakes.
(1)