Refer to Exercise 6.

a. Generate 1000 bootstrap samples from these data. Find the 2.5 and 97.5 percentiles.

b. Compute a 95% bootstrap confidence interval for the mean compressive strength, using method 1 as described on page 390.

c. Compute a 95% bootstrap confidence interval for the mean compressive strength, using method 2 as described on page 390.

Refer to Exercise 6.

In Example 5.20 the following measurements were given for the cylindrical compressive strength (in MPa) for 11 beams:

One thousand bootstrap samples were generated from these data, and the bootstrap sample means were arranged in order. Refer to the smallest value as Y₁, the second smallest as Y₂, and so on, with the largest being Y₁₀₀₀. Assume that Y₂₅ = 38.3818, Y₂₆ = 38.3818, Y₅₀ = 38.3909, Y₅₁ = 38.3918, Y₉₅₀ = 38.5218, Y₉₅₁ = 38.5236, Y₉₇₅ = 38.5382, and Y₉₇₆ = 38.5391.

Method 1:

Method 2: