arlneDetermine whether the samples are independent or related. 1. A police department wants to assess the effects of an obvious radar trap on the speeds of cars. Ten cars are randomly selected on a highway, and their speeds are measured just before a radar trap comes into view and right after they pass the obvious radar trap.
arlneDetermine whether the samples are independent or related.
1. A police department wants to assess the effects of an obvious radar trap on the speeds of cars. Ten cars are randomly selected on a highway, and their speeds are measured just before a radar trap comes into view and right after they pass the obvious radar trap.
2. A company involved in a large volume of business by mail decides to test whether there is a difference in mail delivery between those items brought to a post office compared to those put in a corner mailbox. A random sample of 100 customers from the same city was selected, and their letters were mailed from the post office. Then another random sample of 100 customers was selected, but their letters were sent from the corner mailbox. The company measured how many days it took to deliver the letters for the two random samples.
3. Two formulations of a new whitening soap are compared to their whitening effect. A random sample of 40 potential users of the soap is selected. Each person uses a randomization mechanism to determine which formulation is applied on the left arm so that the other formulation is applied on the right arm. After two weeks, they measured the effect of each formulation.
4. The school principal wishes to determine if the grade 6 boys are better in mathematics than the grade 6 girls. A random sample of boys was selected. Then a random sample of girls was selected. All of the students in the two random samples were asked to take a standardized test in mathematics, and their scores were determined.
5. A science teacher has developed new teaching materials and wants to evaluate the effectiveness of these materials in improving the students' comprehension. Before sampling, the teacher formed pairs of students so that students belonging to the same pair received about the same final grade in science the previous term. The teacher then selected a sample of pairs of students. The teacher randomly selects which student in each pair will be taught using the new materials so that the other one will be taught using the old materials. At the end of the term, all the students in the sample were given a standardized test.
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Determine whether the samples are independent or related.
2. A company involved in a large volume of business by mail decides to test whether there is a difference in mail delivery between those items brought to a post office compared to those put in a corner mailbox. A random sample of 100 customers from the same city was selected, and their letters were mailed from the post office. Then another random sample of 100 customers was selected, but their letters were sent from the corner mailbox. The company measured how many days it took to deliver the letters for the two random samples.