For a standard normal distribution, what is the approximate probability that a randomly selected value lies between -2 and 2?
0.6826
0.9544
0.9974
0.5000
Show the answer and explanation
Correct answer
B. 0.9544
Principle or equation
The empirical rule: for a normal distribution, about 68% of data lies within 1 standard deviation, 95% within 2, and 99.7% within 3.
Why this answer is correct
For a standard normal distribution, the probability that Z is between -2 and 2 is approximately 0.9544 (95.44%).
Example
For between -1 and 1, the probability is approximately 0.6826.
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