Module 8: Descriptive Statistical Methods

Question 1

What are the 4 levels of measurement in order of lowest to highest?

Answer 1

1. Nominal
2. Ordinal
3. Interval
4. Ratio

Question 2

Which levels of measurement are categorical and which are continuous?

Answer 2

Categorical: Nominal and Ordinal
Continuous: Interval and Ratio

Question 3

How can the nominal level of measurement be described?

Answer 3

Assigning numbers to classify characteristics into categories. Categories are mutually exclusive (participants fit into only one category)

Question 4

How can the ordinal level of measurement be described?

Answer 4

Sorting people based on their relative ranking of an an attribute.
Ex- military rank, pain scale

Question 5

How can the interval level of measurement be described?

Answer 5

Equal numerical distance between points on a scale.

Ex- temperature, amount of money in the bank (no true zero, neg. balance)

Question 6

How can the ratio level of measurement be described?

Answer 6

Interval level data that has a true zero.

Ex- most VS, weight, etc.

Question 7

What is the goal of descriptive statistics?

Answer 7

To summarize and describe quantitative data

Question 8

Which types of data can be averaged?

Answer 8

Interval and Ratio

Question 9

What is used to organize raw numerical data?

Answer 9

Frequency distribution

Question 10

In frequency distributions a set of data can be described in terms of what 3 characteristics?

Answer 10

1. Distribution of values
2. Central tendency
3. Variability

Question 11

Symmetric distributions are _____ _______.

Answer 11

mirror images

Question 12

Assymmetric distributions can be ____ ____ or ____ ____

Answer 12

Positively skewed or negatively skewed

Question 13

What is an example of data that could be positively skewed and what way does the graph’s tail face?

Answer 13

Tail is longer to the R
Ex- income, most people have low to moderate incomes and are at the upper end of the distribution with few people earning very high incomes

Question 14

What is an example of data that could be negatively skewed and what way does the graph’s tail face?

Answer 14

Tail is longer to the L

Ex- age of death, most people are at the upper end of the distribution with few people dying at an early age

Question 15

Modality related to distribution shapes describes:

Answer 15

The number of peaks

Unimodal, multimodal

Question 16

What shape is a normal distribution?

Answer 16

Bell curve

Question 17

What can the center of a normal distribution be thought of as?

Answer 17

The average

Question 18

A single number that represents a distribution of values is known as:

Answer 18

central tendency

Question 19

Types of central tendency include:

Answer 19

Mean: average
Median: midpoint when ordered numerically
Mode: most frequent

Question 20

Which term describes how spread out or dispersed the data are?

Answer 20

Variability

Question 21

What is range and why is it unstable?

Answer 21

The highest - the lowest score

Only used as gross descriptive index, outliers may skew

Question 22

What variability index is the average amount of deviation of values from the mean and is calculated using every score?

Answer 22

Standard deviation
(also the square root of variance)

Question 23

What is standard deviation useful for?

Answer 23

Describing a distribution and interpreting individual scores

Question 24

True or False: Assigning groups randomly is a means of providing control to a non-experimental study design?

Answer 24

False

Question 25

What describes how far from a mean a particular score is?

Answer 25

Variance