A new thermostat has been engineered for the frozen food cases in large supermarkets. Both the old and new thermostats hold temperatures at an average of 25°F. However, it is hoped that the new thermostat might be more dependable in the sense that it will hold temperatures closer to 25°F. One frozen food case was equipped with the new thermostat, and a random sample of 26 temperature readings gave a sample variance of 4.5. Another similar frozen food case was equipped with the old thermostat, and a random sample of 16 temperature readings gave a sample variance of 13.1. Test the claim that the population variance of the old thermostat temperature readings is larger than that for the new thermostat. Use a 5% level of significance. How could your test conclusion relate to the question regarding the dependability of the temperature readings? (Let population 1 refer to data from the old thermostat.) (a) What is the level of significance? (b) Find the value of the sample F statistic. (Round your answer to two decimal places.) What are the degrees of freedom? dfN =? dfD =? (c) Find or estimate the P-value of the sample test statistic. (Round your answer to four decimal places.)
A new thermostat has been engineered for the frozen food cases in large supermarkets. Both the old and new thermostats hold temperatures at an average of 25°F. However, it is hoped that the new thermostat might be more dependable in the sense that it will hold temperatures closer to 25°F. One frozen food case was equipped with the new thermostat, and a random sample of 26 temperature readings gave a sample variance of 4.5. Another similar frozen food case was equipped with the old thermostat, and a random sample of 16 temperature readings gave a sample variance of 13.1. Test the claim that the population variance of the old thermostat temperature readings is larger than that for the new thermostat. Use a 5% level of significance. How could your test conclusion relate to the question regarding the dependability of the temperature readings? (Let population 1 refer to data from the old thermostat.)
(a) What is the level of significance?
(b) Find the value of the sample F statistic. (Round your answer to two decimal places.)
What are the degrees of freedom?
| dfN | =? |
| dfD | =? |
(c) Find or estimate the P-value of the sample test statistic. (Round your answer to four decimal places.)
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