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Two catalysts in a batch chemical process are being compared for their effect on the output of the process reaction. A sample of 10 batches was prepared using catalyst 1 and gave an average yield of 85 with a sample standard deviation of 3. A sample of 14 batches was prepared using catalyst 2 and gave an average yield of 80 and a sample standard deviation of 6. Find a 90% confidence interval for the difference between the population means, assuming that the populations are approximately normally distributed with equal variances. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. C Let μ, be the population mean for catalyst 1 and let μ₂ be the population mean for catalyst 2. The confidence interval is <H₁-H₂ <[ (Round to two decimal places as needed.)

The following data represent the length of time, in days, to recovery for patients randomly treated with one of two medications to clear up severe bladder infections. Find a 90% confidence interval for the difference μ₂-μ₁ between in the mean recovery times for the two medications, assuming normal populations with equal variances. Medication 1 n₁ = 12 x₁ = 15 Medication 2 $₁=1.2 n₂ = 13 X₂ = 19 = 1.9 Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. <H₂-H₁< The confidence interval is (Round to two decimal places as needed.) C

A taxi company is trying to decide whether to purchase brand A or brand B tires for its fleet of taxis. To estimate the difference in the two brands, an experiment is conducted using 16 of each brand. The tires are run until they wear out. The results are given in the table below. Compute a 90% confidence interval for μA - H assuming the populations to be approximately normally distributed. You may not assume that the variances are equal. Brand A x₁ = 35,100 kilometers s₁ = 4800 kilometers Brand B $₂=6100 kilometers x₂ = 38,100 kilometers Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. The confidence interval is <HA-HB< (Round to the nearest integer as needed.) C