Toofley the Chemists own 29 pharmacies. The numbers of packets of a new skin medication sold in each of their shops in a week were:
![158_1965e4e3-1102-43ee-946d-5f14c03e55b1.png](https://secure.tutorsglobe.com/CMSImages/158_1965e4e3-1102-43ee-946d-5f14c03e55b1.png)
(a) Find the mode and range of these data.
(b) Identify the median of the data.
(c) Find the lower and upper quartiles.
(d) Determine the semi-interquartile range.