Step-by-step explanation:
First, find the expected value.
μ = 0 (0.28) + 1 (0.37) + 2 (0.22) + 3 (0.08) + 4 (0.05)
μ = 1.25
Now find the standard deviation.
σ² = (0−1.25)² (0.28) + (1−1.25)² (0.37) + (2−1.25)² (0.22) + (3−1.25)² (0.08) + (4−1.25)² (0.05)
σ² = 1.2075
σ = 1.099
If we were to select many boxes of bulbs randomly, the number of defective bulbs would typically vary about 1.099 from the mean.
