Exam 35: Statistical Methods

Stefan has collected a large amount of data in a study designed to test the effectiveness of a new drug meant to slow the progression of Alzheimer's disease. To test whether the drug was effective in a group of participants who received it, in comparison to a group that received a placebo, which type of statistics should Stefan use?

The formula for the standard deviation is

Beth has designed a study to examine whether a new method of learning historical facts will improve the ability of sixth-grade students to recall such facts. The assumption there will be no difference in the recall ability of a group of sixth graders who use the new method, and those who do not, is the

A professor who has two sections of the same course gives an exam. Both classes have the same mean score on the exam. However, in Class A most students scored relatively close to the mean, while in Class B many students scored either much higher or much lower than the mean. Which statement best describes the distribution of grades for the two classes?

Eric has collected data on the relationship between the number of hours the employees at a large number of corporate headquarters spend working on their computers and the profits of the corporations. His scatter diagram of the data shows it clusters near a line running from the bottom right corner to the top left corner. This shows the correlation is

Generally, the MINIMUM requirement for statistical significance is that there is less than ____ that the observed results are due to chance.

It is safest to say that conclusion based on empirical data

When a trait is normally distributed, most scores fall ____ the center of the distribution and the number of scores ____ the center of the distribution.

When a distribution of scores includes a few extreme scores (either extremely high or extremely low) the ____ usually provides the best index of central tendency.

Statistically significant results

When the distribution of scores in a group of scores is symmetrical

The three measures of central tendency tend to converge in a

On the SAT, the mean is 500 and the standard deviation is 100. If you scored 2 standard deviations above the mean, your score would be

Researchers use statistics to do all of the following EXCEPT

The statistical concept of ____ refers to how much the scores in a distribution of scores tend to vary or depart from the mean.

What is the mode of the following set of scores: 1, 2, 5, 6, 6?

Before you construct a histogram you need to

Which of the following correlation coefficients represents the WEAKEST association between two variables?

When a trait has a normal distribution, the unit of measurement used to assess where any score falls in the distribution is the

In a normal distribution, ____ of the scores fall within plus or minus 1 standard deviation of the mean.