Final answer:
To find P(X) for given values, we use the binomial probability formula and normal distribution because the rule of thumb (np and n(1-p) > 10) is met. The z-score helps find the approximate P(X) in a z-table, and the difference between the exact and approximated probabilities is calculated.
Step-by-step explanation:
To compute P(X) using the binomial probability formula for n = 64, p = 0.3, and X = 31, we use the formula:
P(X) = C(n, X) * p^X * (1-p)^(n-X)
Where C(n, X) is the number of combinations of n things taken X at a time. After calculating, we get P(X) (rounded to four decimal places).
For the normal approximation to be used, the rule of thumb is that both np and n(1-p) should be greater than or equal to 10. In our case, with np = 64*0.3 = 19.2 and n(1-p) = 64*0.7 = 44.8, both conditions are satisfied, and thus normal distribution can be used.
Using the normal distribution, we calculate the z-score and find the corresponding area under the normal curve using a z-table to approximate P(X). The probabilities found this way are compared, and the difference between the exact and approximated probabilities is computed (rounded to four decimal places).