A manufacturer of electric irons produces these items in two plants. Both plants have the same suppliers of small parts. A saving can be made by purchasing thermostats for plant B from a local supplier. A single lot was purchased from the local supplier and it was desired to test whether or not these new thermostats were as accurate as the old. The thermostats were to be tested on tile irons on the 550? F setting, and the actual temperatures were to be read to the nearest 0.1?F with a thermocouple. The data are as follows: Find a 95% confidence interval for ?²₁/?²₂ and for ?₁/ ?₂ where ?²₁ and ?²₂ are the population variances of the thermostat readings from the new and old suppliers, respectively.

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New Supplier (°F) 30.3 559.3 549.4 544.0 551.7 566.3 549.9 556.9 559.1 555.0 538.6 551.1 565.4 554.9 550.0 554.9 554.7 536.1 569.1 536.7 558.8 538.8 543.3 Old Supplier (°F) 559.7 534.7 554.8 545.0 544.6 538.0 550.7 563.1 551.1 554.5 553.0 538.4 555.0 553.8 538.8 564.6 548.3 552.9 535.1 548.7 544.8 558.4 560.3