Textbook Notes (270,000)

CA (160,000)

McMaster (10,000)

PNB (70)

PNB 2XE3 (4)

Nikol Piskuric (3)

Chapter 4

School

McMaster UniversityDepartment

Psychology, Neuroscience & BehaviourCourse Code

PNB 2XE3Professor

Nikol PiskuricChapter

4This

**preview**shows half of the first page. to view the full**1 pages of the document.**PNB 2XE3: Descriptive Statistics Winter 2015

Dr. Piskuric

PRE-LAB 2: Chapter 4

1. Make up a set of data for which the mean is greater than the median. (4.4)

4,4,5,6,7,8,48

Mean: 11.7

Median: 6

2. A group of 20 rats running a straight alley maze required the following number of

trials to perform a predetermined criterion. The frequency distribution follows.

Trials to reach criterion: 18 19 20 21 22 23 24

Number of rats: 3 4 3 4 3 2 1

Calculate the mean, median and mode number of trials to criterion for this group.

(Modified from 4.7)

Mean: 7.35

Median: 20.5

Mode: 19 and 21

3. Create a sample of ten numbers that has a mean of 8.6. How did you accomplish this?

(The answer will help you later to understand the concept of degrees of freedom.)

(4.10)

Mean =

∑X

N

8.6 =

∑X

10

86 =

∑X

therefore the ten numbers could be: 1+2+3+4+5+6+7+8+9+41 = 86

4. Why is the mode (but not the mean and median) an acceptable measure for nominal

data? (4.15)

By: Tasfia Ahsan

TA: Aaron

1320425

###### You're Reading a Preview

Unlock to view full version