Hi,
can someone help me to understand this question?
The probability that a normally distributed random variable will be more than two standard deviations above its mean is:
a) 0.9772
b) 0.0228
c) 0.4772
Why the answer “b” is correct? I think its “a”.
0.9772 is the probability than a normally distributed random variable will be two standard deviations above its mean or less, not that it will be more than two standard deviations above its mean.
is it not 0.9545 for 2 standard deviations?
That’s a 2-tail probability; this is a 1-tail analysis.