Descriptive Statistics is the branch of statistics that uses a sample to draw a conclusion about a population.

• True

• False

• not always true

• none of the above

The most important advantage of experiments over observational studies is

• we can study the relationship between two or more explanatory variables.

• we can use randomization to avoid bias in designing an experiment.

• a well-designed experiment can give good evidence that the treatments actually cause the response.

• an experiment can compare two or more groups.

____________ are variables measured on a numeric scale.

• Categorical variables

• Variables x

• Statistic

• Quantitative variables

A psychologist wants to know if adults with normal vision can be fooled by a certain optical illusion. She recruits 50 students from her PSY 120 class and finds that 42 of them are fooled by the illusion. The population in this study is

• the 50 students who served as subjects.

• all adults with normal vision.

• all students in the PSY 120 class.

• the 42 students who were fooled.

An opinion poll asks a sample of 1100 people whether they support reducing the number of legal immigrants to the U.S.; 53% of these 1100 people say "Yes." The number 53% is a

• parameter

• sample

• bias

• statistic

Examples of categorical variables are

• the name of the college a student attends and a student's class rank, such as 25th out of 364.

• a student's weight in kilograms and a student's gender (male or female).

• a student's class rank, such as 25th out of 364 and a student's gender (male or female).

• the name of the college a student attends and a student's gender (male or female).

The student newspaper runs a weekly question that readers can answer online or by campus mail. One question was "Do you think the college is doing enough to provide student parking?" Of the 136 people who responded, 79% said "No." The number 79% is a

If we take many simple random samples from the same population, we expect.....

• a problem with a voluntary response.

• the values of the statistic to vary from sample to sample.

• the same values of the statistic for each sample.

• a different value of the parameter for each sample.

The number of pages in a telephone book is ___________

level of measurement.

• nominal

• ordinal

• interval

• ratio

A variable represents a characteristic of an individual. It can take different values for different individuals.

• True

• False

• Not always

• None of the above