Answer:
0.6247
Step-by-step explanation:
The formula for calculating a Z-score is Z = (X - μ)/σ,
where x is the raw score
μ is the population mean
σ is the population standard deviation.
From the question,
μ = 51, σ = 10. We are to find P(36 ≤ X ≤ 56)
Step 1
Find the Probability of X ≤ 36
μ = 51, σ = 10
Z = (X - μ)/σ
Z = 36 - 51/ 10
Z = -15/10
Z = -1.5
We find the Probability of Z = -1.5 from Z-Table
P(X <36) = P(X = 36) = P(Z = -1.5)
= 0.066807
Step 2
Find the Probability of X ≤ 56
μ = 51, σ = 10
Z = (X - μ)/σ
Z = 56 - 51/ 10
Z = 5/10
Z = 0.5
We find the Probability of Z = 0.5 from Z-Table:
P(X < 56) = P(X = 56) = P(Z = 0.5)= 0.69146
Step 3
Find P(36 ≤ X ≤ 56)
P(36 ≤ X ≤ 56) = P(X ≤ 56) - P(X ≤ 36)
= P( Z = 0.5) - P(Z = -1.5)
= 0.69146 - 0.066807
= 0.624653
Approximately to 4 decimal places , P(36 ≤ X ≤ 56) = 0.6247
