Answer:
67.9 min < μ < 113.5 min
Step-by-step explanation:
Calculation to determine the confidence interval estimate
First step is to find alpha (α/2)
α =1-0.98
α=0.02/2
α= 0.01
Second step is to determine ± zα/2
z-score of 1.0000 - 0.0100 = .9900 using normal distribution table
z-score = ± 2.33
Now Let determine the confidence interval estimate using this formula
X ± zα/2(σ/√n)
Where,
Confidence Interval (CI) = .98
X = 90.7
n = 20
σ = 43.7
Let plug in the formula
Confidence interval estimate = 90.7 ± 2.33 (43.7/√20)
Confidence interval estimate= 90.7 ± 22.76786775
Confidence interval estimate=90.7 - 22.76786775 < μ < 90.7 + 22.76786775
Confidence interval estimate= 67.9 min < μ < 113.5 min
Therefore the confidence interval estimate will be 67.9 min < μ < 113.5 min