Answer Happy

A random sample of size n₁ = 29, taken from a normal population with a standard deviation o, = 6, has mean x₁ = 82. A second random sample of size n₂ = 35, taken from a different normal population with a standard deviation 0₂=3, has a mean x₂ = 33. Find a 98% confidence interval for μ₁ −µ₂. Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. The confidence interval is<H₁-H₂< (Round to one decimal place as needed.)

Two kinds of thread are being compared for strength. Fifty pieces of each type of thread are tested under similar conditions. Brand A has an average tensile strength of 78.3 kilograms with a population standard deviation of 5.3 kilograms, while brand B has an average tensile strength of 87.3 kilograms with a population standard deviation of 6.2 kilograms. Construct a 95% confidence interval for the difference of the population means. Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. The confidence interval is <HA-HB< (Round to two decimal places as needed.)