Write About It 1. When constructing a condence interval for [,L when a is known, we assume that we have a simple random sample, that 0' is known, and that either the sample size is large (n > 30) or the population is approximately normal. Why is it necessary for these assumptions to be met? 2. What factors can you think of that may affect the width of a condence interval? In what way does each factor affect the width? To answer A A A 1, s :6 t '3 ,andp z Pl P). W' n n these questions, you must look at how the margin oferror is calculated in the formulas E __ z