05 - basic statistics concepts

Question 1

Why we need statistics (2 reasons)

Answer 1

OBJECTIVE way of interpreting a collection of observations
REDUCE data to useful value that represents a trait about the data

Question 2

Categorical measurements

Answer 2

Qualitative
( “which type” and “which category”)

Question 3

Continuous measurements

Answer 3

Quantitative
“how much” and “how many”

Question 4

4 different scales of measurement

Answer 4

Nominal
Ordinal
Interval
Ratio

Question 5

Which 2 scales are categorical

Answer 5

Nominal
Ordinal

Question 6

Which 2 scales are continuous

Answer 6

Interval
Ratio

Question 7

Nominal scale

Answer 7

“Name”
Associated with categorial data

Question 8

Ordinal scale

Answer 8

“Order”
Associated with categorical data
Any rank ordering

Question 9

Limitation of ordinal scale

Answer 9

Don’t always know the amount of difference between each piece of data

Question 10

Interval scale

Answer 10

“equal intervals”
Associated with continuous data
Has all the properties of ordinal data plus equality of units
May contain an arbitrary zeron

Question 11

Ratio scale

Answer 11

Ratio statements can be made
Associated with continuous data
Has all the properties of interval scale plus an absolute zero

Question 12

What is an arbitrary zero?

Answer 12

Does not reflect the absence of the trait being measured

Question 13

What is an absolute zero?

Answer 13

Absence of the trait

Question 14

Summary - nominal

Answer 14

Values are named

Question 15

Summary - ordinal

Answer 15

Values are named and ordered

Question 16

Summary - interval

Answer 16

Values are named and ordered and have equal intervals

Question 17

Summary - Ratio

Answer 17

Values are named and ordered and have equal intervals and have an absolute zero

Question 18

Statistical foundations of measurements theory (7)

Answer 18

• Frequency distribution
• Mean
• Variance
• Standard deviation
• Normal curve
• Correlation coefficient
• Standard error of measurements

Question 19

What is frequency distribution?

Answer 19

Number of times each scores is represented in the data set

Question 20

What is mean?

Answer 20

Sum of the observation divided by the number of observations

Question 21

What is variance?

Answer 21

Measure of variability of the data set

Question 22

What is standard deviation?

Answer 22

Square root of the variance

Question 23

What is normal curve?

Answer 23

Symmetric frequency distribution
Z-score

Question 24

What is correlation coefficient?

Answer 24

The degree of linear relationship between two variables

Question 25

What is standard error of measurements (SEM)?

Answer 25

Relate the given score to the “true” score
Determine the amount of measurements error of a tool on a set of repeated measures

Question 26

Descriptive statistics

Answer 26

Used to describe the group from which data is collected
No intention to generalize beyond that group or point in time

Question 27

Inferential statistics

Answer 27

Used when making generalizations or inferences to other groups or variables

Question 28

Population

Answer 28

All-inclusive group

Question 29

Sample

Answer 29

Representative subset of the population

Question 30

Random samples

Answer 30

The sample should be selected randomly so that it represents the larger population

Question 31

Stratified random sampling

Answer 31

When the population has subgroups and we want to sample proportionately from those subgroups

Question 32

Convenience sample

Answer 32

Random sampling is not always possible
However, we should still aim for the sample to be representative

Question 33

Randomization into groups

Answer 33

Within the sample, people should be randomly assigned to groups