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Chapter 9: Q.5 (page 546)

During the winter months, the temperatures at the Colorado cabin owned by the Starnes family can stay well below freezing (32°F or 0°C) for weeks at a time. To prevent the pipes from freezing, Mrs Starnes sets the thermostat at 50°F. The manufacturer claims that the thermostat allows variation in-home temperature of S 3°F. Mrs Starnes suspects that the manufacturer is overstating how well the thermostat works.

Short Answer

Expert verified

standard deviation = 3oF as per null hypothesis

standard deviation is greater than 3oF as per alternative hypothesis.

Step by step solution

01

introduction

Given,

The temperatures at the Colorado cabin owned by the Starnes family can stay well below freezing for weeks at a time.

The standard deviation claimed by the manufacturer is 3oF

02

explanation

Calculating the null and alternative hypotheses,

standard deviation σ= 3oF as per null hypothesis

⇒H0:σ=3

standard deviation is greater than 3oF as per alternative hypothesis.

⇒Ha:σ>3

The standard deviation is 3oF as per null hypothesis and standard deviation is greater than3o F as per alternative hypothesis.

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