Question

Let x be a language examination score data. If x∼N(60,10^2), find Pr{x≥70}.

Answer 1

Answer:

P(X >= 70) = 0.1587

Step-by-step explanation:

Given in the question

X is normally distributed with

Mean (μ) = 60

Variance = 100

Standard deviation (σ) = 10

We need to calculate probability

P(X >= 70) = 1 - P(X < 70)

Here we will use standard normal distribution so Z-score can be calculated as

Z-score = (X - μ)/σ = (70-60)/10 = 1

from Z table we found p-value

P(X >= 70) = 1 - P(X < 70) = 1 - 0.8413 = 0.1587

So P(X >= 70) = 0.1587