Question

The following data represent the pH of rain for a random sample of 12 rain dates in a particular region. A normal probability plot suggests the data could come from a population that is normally distributed. A boxplot indicates there are no outliers. The sample standard deviation is sequals0.344. Construct and interpret a 99​% confidence interval for the standard deviation pH of rainwater in this region

Answer 1

Solution :

Given that,

s = 0.344

s² = 0.118336

²_L = ²_/2,df = 26.757

²_R = ²_{1 - /2,df} = 2.603

The 99% confidence interval for is,

(n - 1)s² / ²_/2 < < (n - 1)s² / ²_{1 - /2}

  11 * 0.118336 / 26.757 < < 11 * 0.118336 / 2.603

0.2206 < < 0.7071

(0.2206 , 0.7071 )