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An experiment might be preferred over an observational study because…

You and your friend conduct separate observational studies to estimate the proportion of PC students that prefer Hawaiian pizza with pineapple and bacon over other varieties of pizza. Consider the population to be all PC students. Your friend randomly selects 20 students from the school and uses the sample proportion of students who prefer Hawaiian pizza to estimate the population proportion of students who prefer Hawaiian pizza. You also randomly select your own sample of 20 students and find the sample proportion of students who prefer Hawaiian pizza.   QUESTION: Are the populations the same for your friend’s study and for yours?

A 13.5-m boom (the part between points A and B), of a crane lifting a 3000-kg load is shown below. The center of mass of the boom is at its geometric center, and the weight of the boom is 2400 lb. For the position shown, calculate tension T in the cable and the force at the axle A.  

This is another question about the article in the October 2018 issue that referred to a study claiming that two-thirds of all portable internet devices in the United States end up in a landfill when they are replaced.   QUESTION: Is this number (two-thirds) a parameter or a statistic?

A solid concrete cylinder (r = 2400 kg/m3) with a diameter of 80.0 cm and a height of 15.0 cm is spinning on a frictionless pivot with an initial rotational velocity of 2.00 RPM (revolutions per minute). You want to stop the cylinder by pressing against the outer edge with a wooden stick, where the coefficient of static friction between the stick and the concrete is 0.750 and the coefficient of kinetic friction is 0.600. If you want to stop the cylinder in exactly 30.0 seconds, with what force must you press the stick against the edge of the cylinder? Recall the moment of inertia of a solid cylinder is ½ MR2. 

The color distinction between white fat and brown fat exists because brown fat

Which of the following organs is described as retroperitoneal?

Visceral pericardium is located

The pancreas produces ________ secretions that include digestive enzymes and hormones, respectively.

 The layer of the skin that contains bundles of collagen and elastic fibers responsible for thestrength of the skin is the ________ layer.