Exam 4: Measures of Central Tendency and Variability

An industrial psychologist observed 8 drill-press operators for one working day. She recorded the number of times each operator pressed the "faster" button instead of the "stop" button to determine whether the design of the control panel was contributing to the high rate of accidents in the plant. The resulting scores were as follows: 5, 2, 8, 2, 3, 2, 4, 12 The variance for this distribution is _________. Assume sample data.

Let's assume that we have determined the salary of all the professors at your school. In plotting the distribution of salaries we notice that it is positively skewed. For this distribution _________.

Given the following set of scores X : 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the mode?

Given the following set of scores X : 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the range?

Identify three measures of central tendency. How do they differ?

Consider two more sets of scores. Notice that the Y scores are just the X scores with a constant value of 10 added to each score. What effect does adding a constant have on the value of the standard deviation? Do you see why? X : 1, 3, 5, 7, 9 Y : 11, 13, 15, 17, 19

When might the median be a better statistic to use for central tendency than the mean? Illustrate your answer by using an example.

A history professor gives a quiz to his class and records the following scores: 13, 11, 11, 9, 12, 13, 16, 14, 11, 10, 8, 13, 20. The variance for this distribution is _________. Assume sample scores.

If 10 points were added to each score in a distribution, which of the following will happen?

The mode is used extensively in the behavioral sciences.

Compare and contrast the mean, median, and mode with respect to a) their sensitivity to extreme scores and b) their subjectivity to sampling variation.

An industrial psychologist observed 8 drill-press operators for one working day. She recorded the number of times each operator pressed the "faster" button instead of the "stop" button to determine whether the design of the control panel was contributing to the high rate of accidents in the plant. The resulting scores were as follows: 5, 2, 8, 2, 3, 2, 4, 12 The standard deviation for this distribution is _________. Assume sample data.

equals _______ .

In calculating the standard deviation of a sample, we use _________ in the denominator.

The mean weight for team A with 15 members is 140 lbs., the mean weight for team B with 7 members is 135 lbs., and the mean weight for team C with 20 members is 160 lbs. The overall mean weight for all three teams is _________.

Define arithmetic mean.

On a physics exam, the instructor gives a bonus question worth 10 points. The class average (mean) without counting the bonus question is 83. If everyone gets the bonus question correct, the class mean would _________.

Define sum of squares

An industrial psychologist observed 8 drill-press operators for one working day. She recorded the number of times each operator pressed the "faster" button instead of the "stop" button to determine whether the design of the control panel was contributing to the high rate of accidents in the plant. The resulting scores were as follows: 5, 2, 8, 2, 3, 2, 4, 12 The median for this distribution is _________.

= 0