Direct evidence of Newton's universal law of gravitation was provided from a renowned experiment by Henry Cavendish (1731-1810). In the experiment, masses of objects were determined by weighing, and the measured force of attraction was used to calculate the density of the earth. The values of the earth's density, in time order by row, are

5.36	5.29	5.58	5.65	5.57	5.53	5.62	5.29
5.44	5.34	5.79	5.10	5.27	5.39	5.42	5.47
5.63	5.34	5.46	5.30	5.75	5.68	5.85

(a) Find the mean and standard deviation.

(b) Find the median, $Q_{1}$, and $Q_{3}$.

(c) Plot the observations versus time order. Is there any obvious trend?