A marine biologist wants to estimate the mean size of the barnacle Semibalanus balnofdes on a stretch of rocky shoreline. To do so, he uses a map to grid over 100 10-cm square polts on the shore and then randomly selected twenty 10cm. square plots and measured the size of every barnacle in each plot. This is an example of O a cluster sampling. 0 b simple random sampling. 0 C convenience sampling. 0 d stratified random sampling. The Bradley effect is a theory proposed to explain observed discrepancies between voter opinion polls and election outcomes in some elections where a female candidate and a male candidate run against each other. The theory proposes that some voters tend to tell pollsters that they are undecided or likely to vote for a female candidate, and yet, on election day, vote for the male opponent. This is an example of O a nonresponse. O b undercoverage. O C response bias. 0 d bias resulting from question wording. One hundred volunteers who suffer from severe depression are available for a study. Fifty are selected at random and are given a new drug that is thought to be particularly effective in treating severe depression. The other fifty are given an existing drug for treating severe depression. A psychiatrist evaluates the symptoms of all volunteers after four weeks in order to determine if there has been substantial improvement in the severity of the depression. The study would be double blind if O a the psychiatrist evaluating the severity of the depression did not know which treatment the patients had received. 0 b neither drug had any identifying marks on it so the patients do not know which medication they are receiving. the patients were given a placebo. neither the volunteers nor the psychiatrist knew which treatment any person had received. Just before the presidential election of 1936, the magazine Literary Digest predicted incorrectly, as it turned outthat Alf Landon would defeat Franklin Delano Roosevelt. Landon lost in a landslide. It turned out that the magazine had only polled its own subscribers, plus others from a list of automobile owners and a list of people who had telephone service. All three groups had higher than typical incomes during the Great Depression. This is an example of O a response bias. 0 b undercoverage. O C bias resulting from question wording. 0 d non response. An experiment compares the taste of a new spaghetti sauce with the taste of a commercially successful sauce readily available in grocery stores. Each of a number of tasters tastes both sauces (in random order) and says which tastes better. This is called a O a simple random sample. 0 b stratified random sample. 0 C completely randomized design. 0 d matched pairs design. In a medical experiment, physicans are researching the effects of a new motion sickness drug. Because they believe gender might effect the medications effectiveness, they group the experimental units by gender, then randomly assign equal numbers from each group to various treatment groups. This is an example of a O a stratified sampling. 0 b matched pairs design. 0 C randomized block design. 0 d completely randomized design. Researchers wish to determine ifa new experimental medication will reduce the symptoms of allergy sufferers without the side effect of drowsiness. To investigate this question, the researchers randomly assigned 100 adult volunteers who suffer from allergies to two groups. They gave the new medication to the subjects in one group and an existing medication to the subjects in the other group. Fortyfour percent of those in the treatment group and 28% of those in the control group reported a significant reduction in their allergy symptoms without any drowsiness. The principle reason for the use of controls in designing experiments is that it O a allows the experiment's ndings to be generalized to the population. 0 b always allows for the possibility of the placebo effect. 0 C distinguishes a treatment effect from the effects of confounding variables. 0 d creates approximately equal groups for comparison