4. (a) Let \( \left\{X_{n}\right\} \) be a sequence of i.i.d.uniform \( (0,1) \) random variables. Define \( Y=\min \left\{X_{n}\right\} \).
- Show that \( Y \xrightarrow{D} 0 \) and \( Y \stackrel{P}{\rightarrow} 0 \).
[40 Marks]
(b) If \( T_{n}=X_{1}+X_{2}+\cdots+X_{n} \) is the sum of a random sample of size \( n \) with mean \( \mu \) and variance \( \sigma^{2} \), show that \( \frac{T_{n}-n \mu}{\sqrt{n} \sigma} \approx A N(0,1) \) for sufficiently large \( n \).
[30 Marks]
(c) Let \( X_{1}, X_{2}, \ldots \ldots, X_{30} \) be a random sample of size 30 from a Uniform \( [0,1] \) distribution. Find \( P\left(T_{30}<20\right) \) using the results in part (b).
[30 marks]