Psychology Ethics

Lesson 3.1
1. Consider the mode, median, and mean.
(a) Which average represents the middle value of a data distribution? Median

(b) Which average represents the most frequent value of a data distribution? Mode

(c) Which average takes all the specific values into account? Mean
2. What symbol is used for the arithmetic mean when it is a sample statistic? What symbol is used when the arithmetic mean is a population parameter? Statistic, x; parameter, μ

3. When a distribution is mound-shaped symmetrical, what is the general relationship among the values of the mean, median, and mode? The mean, median, and mode are approximately equal

4. Consider the following numbers.
2
3
4
5
5
(a) Compute the mode, median, and mean. 5; 4; 3.8
(b) If the numbers represented codes for the colors of T-shirts ordered from a catalog, which average(s) would make sense? Mode

(c) If the numbers represented one-way mileages for trails to different lakes, which average(s) would make sense? Mean

(d) Suppose the numbers represent survey responses from 1 to 5, with 1 = disagree strongly, 2 = disagree, 3 = agree, 4 = agree strongly, and 5 = agree very strongly. Which average(s) make sense? Median, mode

5. In this problem, we explore the effect on the mean, median, and mode of adding the same number to each data value. Consider the data set 3, 3, 4, 7, 11.
(a) Compute the mode, median, and mean. 3; 4; 5.6

(b) Add 8 to each of the data values. Compute the mode, median, and mean. 11; 12; 13.6

(c) Compare the results of parts (a) and (b). In general, how do you think the mode, median, and mean are affected when the same constant is added to each data value in a set?
Adding the same constant c to each data value results in the mode, median, and mean increasing by c units.

6. Consider a data set of 15 distinct measurements with mean A and median B.
(a) If the highest number were increased, what would be the