Answer
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P(x<-1) = 0.158655
↓Steps Explained:↓
Given X = 85, μ = 105, and σ = 20
Calculate P(X < Z)
Z-score formula
Using the Normal Distribution, Calculate P(X < 85)
| Z = | X - μ |
| σ/√1 |
| Z = | 85 - 105 |
| 20/√1 |
| Z = | -20 |
| 20/1 |
| Z = | -20 |
| 20 |
Z = -1
From the table below, we see that our Z value is = 0.341345
Z-table Lookup Value
The z-table probability runs from 0 to z and -z to 0
Z value = 0.341345
Since that represents ½ of the graph, we subtract our value from 0.5 → 0.5 - 0.341345
P(x<-1) = 0.158655
Final Answer
P(x<-1) = 0.158655Take the Quiz
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