9514 1404 393
Answer:
B. 3.5
Step-by-step explanation:
The given range is 20 ± 7. The empirical rule tells you 95% of scores will fall within μ ± 2σ. We know μ = 20, so 2σ = 7. That is σ = 7/2 = 3.5.
The standard deviation is 3.5.
