Can any one tell me
How we can write P( |B1 - B2 |> 0.1)
equals to 2P( B1 - B2 > 0.1)
What is B1? A random variable? What distribution does it follow? What is B2? The whole question is needed, not just the small scraps you've decided are important.
B1,B2 are random variables and they follow normal distribution.
The full question is:
Bottles of mineral water are delivered to shops in crates containing 12 bottles each. The weights of bottles are normally distributed with mean weight 2kg and standard deviation 0.05kg. The weights of empty crates are normally distributed with mean 2.5kg and standard deviation 0.3kg.
Two bottes are selected at random from a crate. Find the probability that they differ in weight by more than 0.1kg.
Then B = B1 - B2 is also a normally distributed random variable. Its mean is zero and standard deviation is . Read section 3 of this: Normal distribution - Wikipedia, the free encyclopedia
Calculate Pr(-0.1 < B < 0.1) = 2 Pr(0 < B < 0.1) by symmetry.