cant understand

18 Tiana is a quality controller in a clothes factory. She checks for four possible types of defects in shirts. Of the shirts with defects, the proportion of each type of defect is as shown in the table below. Type of defect Colour Fabric Sewing Sizing Probability 0.25 0.30 0.40 0.05 Shirts with defects are packed in boxes of 30 at random. 18 (a) Find the probability that: 18 (a) (i) a box contains exactly 5 shirts with a colour defect [2 marks] 18 (a) (ii) a box contains fewer than 15 shirts with a sewing defect [2 marks] 18 (a) (iii) a box contains at least 20 shirts which do not have a fabric defect. 13 marks1 18 (b) Tiana wants to investigate the proportion, p, of defective shirts with a fabric defect She wishes to test the hypotheses Ho : P = 0.3 H1 : p