The following data represent petal lengths (in cm) for independent random samples of two species of iris. petal length (in cm) of iris virginica: x1; n1 = 35 5.2 5.8 6.5 6.1 5.1 5.5 5.3 5.5 6.9 5.0 4.9 6.0 4.8 6.1 5.6 5.1 5.6 4.8 5.4 5.1 5.1 5.9 5.2 5.7 5.4 4.5 6.4 5.3 5.5 6.7 5.7 4.9 4.8 5.9 5.2 petal length (in cm) of iris setosa: x2; n2 = 38 1.4 1.8 1.4 1.5 1.5 1.6 1.4 1.1 1.2 1.4 1.7 1.0 1.7 1.9 1.6 1.4 1.5 1.4 1.2 1.3 1.5 1.3 1.6 1.9 1.4 1.6 1.5 1.4 1.6 1.2 1.9 1.5 1.6 1.4 1.3 1.7 1.5 1.7 (a) use a calculator with mean and standard deviation keys to calculate x1, s1, x2, and s2. (round your answers to two decimal places.) x1 = s1 = x2 = s2 = (b) let μ1 be the population mean for x1 and let μ2 be the population mean for x2. find a 99% confidence interval for μ1 − μ2. (round your answers to two decimal places.) lower limit upper limit