The mean of the sampling distribution is \( \mu = 50 \), the standard deviation is \( \sigma_{\bar{x}} \approx 1.8257 \), and the probability that the sample mean falls within the range \( [45, 55] \) is approximately \( P \approx 0.9938 \).
Thus, the final answer is:
\[
\boxed{P \approx 0.9938}
\]