Question

Problem 7 In experiment you want to obtain a confidence interval for difference of the strength of two materials. Assume that the fortress of the materials is normally distributed and that the variance () 900 psi2 and the variance (II) 400 psi ?. If due to cost, it is known that the sample size I must be twice the size of sample II. What should be the size of the samples if an error less than or equal to 20 psi is desired with a 99% reliability? (20 pts)

Answer 1

ANSWER:

Given that,

From the question, strength of the materials is normally distributed and

it is known that the sample size I must be twice the size of sample II.

2n₁ =n₂

the size of the samples if an error less than or equal to 20 psi is desired with a reliability of 99% is

Similarly for 2