Answer:
(87.85 ≤ μ ≤ 93.11)
Step-by-step explanation:
Given the data:
91.6, 88.75, 90.8, 89.95, 91.3
Mean, m = Σx / n
n = sample size = 5
Mean = 452.4 / 5 = 90.48
Standard deviation, σ = 3
Zcritical at 95% = 1.96
Confidence interval :
Mean ± Error margin
Error margin = Zcritical*σ/sqrt(n)
Error margin = 1.96 * 3/sqrt(5)
Error margin = 2.630
Lower boundary : 90.48 - 2.630 = 87.85
Upper boundary : 90.48 + 2.630 = 93.11
(87.85 ; 93.11)