A random variable X takes values  and  with probabilities 0.2 and 0.8, respectively. It is transmitted across a channel which adds noise N, so that the random variable at the channel output is . The noise N is independent of X, and is uniformly distributed over the interval. The receiver makes a decision.

Where the threshold  is chosen so as to minimize the probability of error . The minimum probability of error, rounded off to 1 decimal place, is ____________.