The activity R of an unknown radioactive nuclide is measured at hourly intervals. The results found are tabulated as follows:

t (h) | 0 | 1 | 2 | 3 | 4 |

R (MBq) | 100 | 35.36 | 12.51 | 4.42 | 1.56 |

(i) Plot the graph of R versus t and calculate half-life from the graph.

(ii) Plot the graph of ln(R/R_{0}) versus t and obtain the value of half-life from the graph.