Suppose that a state offered voluntary standardized tests to all its third graders and that these data were used in a study of class size on student performance. which of the following would generate selection bias?

a)schools are unable to control for unobservable student ability

b) scores on standardized test are usually recorded with error

c) class size is simultaneously determined with student performance

d)schools with higher-achieving students could be more likely to volunteer to take the test

Tomas is making trail mix using granola and walnuts. he can spend a total of $12 on the ingredients. he buys 3 pounds of granola that costs $2.00 per pound. the walnuts cost $6 per pound. he uses the equation to represent the total cost, where x represents the number of pounds of granola and y represents the number of pounds of walnuts. he solves the equation for y, the number of pounds of walnuts he can buy. answer- b tomas added 6 to both sides of the equation instead of subtracting 6. just took the test

The weight of an object in the water is 7% of its weight out of the water. what is the weight of a 652g object in the water?

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81