MathCastle
Statistics & DataSuperchallengeConfidence Intervals

Confidence Intervals · Superchallenge problem

A normal sampling distribution has standard error 1, so the usual 95% interval for μ\mu is xˉ±1.96\bar x \pm 1.96, of width 3.923.92. An analyst instead builds a 95% interval that puts 4% of the miss probability on the low side and 1% on the high side: (xˉ−z0.99, xˉ+z0.96)(\bar x - z_{0.99},\ \bar x + z_{0.96}), where Φ(z0.99)=0.99\Phi(z_{0.99}) = 0.99 and Φ(z0.96)=0.96\Phi(z_{0.96}) = 0.96. By how much is this interval WIDER than the usual one? Round to two decimal places.