Need help with normal distribution

X.2. Let 32 denote the sample variance from a random sample of size n. = 51 from a normal distribu tion with variance 02 = 4. (a) Find the probability that 32 > 5.053. Explain your method. (b) For large 1:, we may regard a x2 random variable with 1) degrees of freedom as an approximately normal random variable X with mean I\" = v and variance 0'2 = 21:. Use normal approximation to instead estimate 1%.?\" > 5.053). By normal approximation we mean that Z = (X x)/JX is apprcocimately standard normal