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 |
Tiana wants to investigate the proportion, \(p\), of defective shirts with a fabric defect.
She wishes to test the hypotheses
$$H_0 : p = 0.3$$
$$H_1 : p < 0.3$$
She takes a random sample of 60 shirts with a defect and finds that \(x\) of them have a fabric defect.
- Using a 5% level of significance, find the critical region for \(x\).
[5 marks]
- In her sample she finds 13 shirts with a fabric defect.
Complete the test stating her conclusion in context.
[2 marks]