he aim of a study is to test the ratio of variances in the weight of two groups of rats being under a certain drugs A ( group 1) and B ( group 2). A random sample of 17 rats was selected from group 1and 11 rats from group 2, Then their weight were recorded. The results are shown in the following table sd Median Mean n 1.05 3.0 3.5 17 group 1 1.15 2.0 2.20 11 group 2 F19.16,0.025=0.386 F15,12,0.05 =0.404 F16.10,0.025=0.335 F19,16,0.05=0.451 F15,12,0.1 0.496| F16,10,0.05 =0.401 F16,19,0.025 0.371 F12.15,0.05 =0.382 F10,16,0.0025 =0.286| F16.19,0.05=0.437 F1215,01=0.475 F10,16,0.05 =0.354 Construct a 95% confidence interval for the ratio of the variances. [ Write only the final result in the box below

Is the Chebyshev's rule used only with populations? Are samples used as well?

A study, conducted by Jackson et al. and published in the journal Cancer Causes and Control in 2009, examined 33,938 women aged 40 to 84 years old who resided in California and who reported having had a mammogram within the last 2 years. The researchers were interested in characteristics of women who routinely obtain mammograms, as suggested by the American Cancer Society, to detect breast cancer. The table below provides a column that refers to the sample size and provides characteristics of the 33,938 women who were included in the study who reported having had a mammogram. Sample size Total |33,938 Race/Ethnicity Latina 3458 African American 1923 Asian/Pacific Islander 2807 White 24,487 Other 1263 Marital Status Married/Living with partner |17,916 Not currently married 16,022