Question

The cost of 5 gallons of ice cream has a variance of 64 with a mean of 34 dollars during the summer. What is the probability that the sample mean would differ from the true mean by more than 1.1 dollars if a sample of 38 5-gallon pails is randomly selected? Round your answer to four decimal places.

Answer 1

Probability[(X - μ) < 1.1] = 0.6046

Explanation:

Given:

σ² = 64

Mean μ = 34

Find:

Probability[(X - μ) < 1.1]

Computation:

Standard deviation σ = √σ²

Standard deviation σ = √64

Standard deviation σ = 8

Probability[(X - μ) < 1.1] = Probability[-1.1 < (X - μ) < 1.1]

Probability[(X - μ) < 1.1] = Probability[-1.1/(8/√38) < (X - μ) < 1.1/(8/√38)]

Using z table

Probability[(X - μ) < 1.1] = 0.6046