Chapter 19 - From Data Production to Inference: Part III Review - Test Yourself - Page 446: 19.27

(b)

Here, we have n = 14, x̅ = 172, σ = 41 $σ_{x̅} = \frac{σ}{\sqrt n} = \frac{41}{\sqrt 14} = 10.96$ For the 90% C.I, we have: z = 1.645 E = (1.645)(10.96) = 18.03 Upper Bound = 172 + 18.03 = 187.89 Lower Bound = 172 - 18.03 = 156.11