Question

This question is worth 10 marks.

You are comparing the sizes of cat’s eye snails, Lunella smargada, inside and outside a Rāhui (reserve where fishing is banned) in Kaikōura. Cat’s eye snails are a delicacy, but only the largest snails are taken to be eaten. You therefore expect that the population of snails in the Rāhui will be larger on average than snails from outside the Rāhui. You have size data (shell diameter in mm) from 200 snails in the low tide zone in the Rāhui and from 245 snails in the low tide zone outside of the Rāhui. The data are summarized below:

Variable	Rāhui	Outside
n	200	245
Σ (x)	6286.03	4486.20
Σ (x2)	207351	93061.07
variance sx2	49.15	44.73

1-Write an appropriate null hypothesis for this two-sample t-test

2-What is the mean size of cat’s eye snails in the Rāhui to 2 decimal places?

3-What is the mean size of cat’s eye snails outside of the Rāhui to 2 decimal places?

4-Calculate the standard error of the differences between means to 2 decimal places

Answer 1