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Given X = 240, μ = 250, and σ = 7.14
Calculate P(X < Z)
Using the Normal Distribution, Calculate P(X < 240)
Z = | X - μ |
σ/√1 |
Z = | 240 - 250 |
7.14/√1 |
Z = | -10 |
7.14/1 |
Z = | -10 |
7.14 |
Z = -1.401
From the table below, we see that our Z value is = 0.419243
The z-table probability runs from 0 to z and -z to 0
Z value = 0.419243
Since that represents ½ of the graph, we subtract our value from 0.5 → 0.5 - 0.419243
P(x<-1.401) = 0.080757