Exam 11: Experiments and Observational Studies

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test.In a study, there are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (method A, method B, and method C).The number of students participating in the study is 258.Students are randomly assigned to a teaching method and teacher.Identify the levels of The factor "teaching method."

It was discovered that a larger proportion of children who slept with nightlights later developed nearsightedness, compared to children who did not sleep with nightlights.The headlines read, "Leaving a light on for you children causes nearsightedness!" Later it was pointed out that nearsighted people have more trouble seeing in the dark and are more likely to leave lights on at night for their kids.And those same nearsighted parents are likely to have nearsighted kids.This is an example of

A survey of online consumers asked respondents to indicate how much money they spent for online purchases during the most recent Christmas holiday season.These data were analyzed to see if gender and income level influence the amount consumers spend online for holiday shopping.Which of the following statements is true? I.This is an experimental study. II.This is a randomized block design. III.This is an observational study.

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo.The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded.Identify the levels of the factor.

In order to see which variety of apple tree produces more fruit, a farmer sets up an experiment.He has three plots of land with different soil and natural water availability.Each plot has room for eight trees.The farmer randomly selects four locations in each plot for the first variety of tree and the other four get the second variety.This experiment is…

Quality control engineers fire tiles made with this new material at three different temperature settings (1500°F, 1800°F and 2200°F) and for four different times (2 hours, 6 hours, 10 hours and 12 hours) to determine the optimal parameter settings for firing that will result in tiles with high flexural strength.The response variable in this experiment is

An advocacy group is interested in determining if gender (1 = Female, 2 = Male) affects executive level salaries.They take a random sample of executives in three different industries: (1 = Consumer Goods, 2 = Financial, 3 = Health Care).Salary data are collected. Which of the following statements is true? I.This is an experimental study. II.This is an observational study. III.This is a randomized block design.

Do energy snack bars improve afternoon alertness? 100 factory workers were randomly assigned to two groups.One group ate energy snack bars at lunch and the other group ate placebo snack bars.At the afternoon break (approximately 1-1/2 hour after lunch), a significant increase in alertness was observed.Later analysis of the experiment results showed 87% of the participants exhibiting increased alertness were from the group which ate Energy snack bars.

Which is not a critical part of designing a good experiment?

Which is true about randomized experiments? I.Randomization reduces the effects of confounding variables. II.Random assignment of treatments allows results to be generalized to the larger Population. III.Blocking can be used to reduce the within-treatment variability.

A Columbia University study linked soda consumption to behavior problems in children. Researchers examined data from a previous study that followed 2929 mother-child pairs.One survey asked about behaviors of the child and also about soda consumption.They found that the more soda the kids drank, the more behavior problems they had.What aspect of a well- designed experiment is absent from this study?

The experiment is run once for each combination of brand of AAA batteries and device (TV remote, hand-held game, flashlight and digital camera).The twelve runs are ordered randomly.The time (in minutes) that each battery lasts under continuous usage is recorded. Which of the following statements is true about this design?

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo.The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded.Identify the factor in the experiment.

Is the aspirin produced by World's Best Pharmaceutical Company better than that of a competitor at relieving headaches? 200 headache suffers are chosen at random.Migraned testing Service administers the experiment and provides the results evaluation.Three levels are made: participants receive contents from Bottle A, Bottle B, or Bottle C Other than the fact that one bottle contains placebo aspirin, no other information is given to the testing

An education researcher was interested in examining the effect of the teaching method andthe effect of the particular teacher on students' scores on a reading test.In a study, there aretwo different teachers (Juliana and Felix) and three different teaching methods (method A, Method B, and method C).The number of students participating in the study is 258.Students are randomly assigned to a teaching method and teacher.Identify the treatments.

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test.In a study, there are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (method A, method B, and method C).The number of students participating in the study is 258.Students are randomly assigned to a teaching method and teacher.Identify the factor(s) In the experiment.

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test.In a study, there are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (method A, method B, and method C).The number of students participating in the study is 258.Students are randomly assigned to a teaching method and teacher.Identify the response Variable measured.

A company has tried to improve the effectiveness of its dishwashing detergent and wants to see if it works better than the original formula.They use 6 identical new dishwashers and load them identically with dirty dishes.Three packs of each of the two types of detergent are used, and they are randomly assigned to one of the six dishwashers.After the load is run, They rate each load for overall cleanliness.Which of the following is true?

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a lowdosage of an experimental drug, the second group received a high dosage of the drug, and thethird group received a placebo.The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded.Identify the response variable measured.

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the experimental drug, and the third group received a placebo.The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded.Identify the treatments.