Quiz 1

Question 1

Field of Statistics

Answer 1

The theory of decision making

Question 2

Population

Answer 2

Collection of all outcomes, responses, counts of interest

Question 3

Sample

Answer 3

Subset of population

Question 4

Parameter

Answer 4

Numerical characteristic describing a population

Question 5

A Statistic

Answer 5

Numerical characteristic describing a sample

Question 6

Types of Data

Answer 6

Qualitative and Quantitative

Question 7

Qualitative Data

Answer 7

Qualities such as eye color, gender, hair color, etc.

Question 8

Quantitative Data

Answer 8

Discrete: finite or countable infinite number of possibilities
Continuous: uncountably infinite number of possibilities
Ex. Weight, age, height

Question 9

2 Types of Statistics

Answer 9

1. Descriptive: used for organization and display of data

2. Inferential: used to draw conclusions about a population

Question 10

Types of Samples

Answer 10

1. Random Sample
2. Simple Random Sample
3. Probability Sample
4. Stratified Sample
5. Cluster Sample
6. Systematic Sample

Question 11

Random Sample

Answer 11

Every member of population has equal chance of being selected

Question 12

Simple Random Sample

Answer 12

Every possible group of the same size has the same chance of selection

Question 13

Probability Sample

Answer 13

All members of population have a chance to be selected, not all equal

Question 14

Stratified Sample

Answer 14

Break population up into homogenous groups and take a SRS from each group proportionally

Question 15

Cluster Sample

Answer 15

Sample entire subgroup

Question 16

Systematic Sample

Answer 16

Sample every Kth person

Question 17

Density Histogram

Answer 17

Data
Bins
Step 1: Fraction = # of occurrences / n
Step 2: Height = frac / bin width
* subtract to find bin width don't add them all!
The area created by a D.H. is 1

Question 18

Notation

Answer 18

• n = sample size
• Xi = ith value
• X(i) = ith smallest value
• X(1) = Min
• X(n) = Max

Question 19

Robustness

Answer 19

A statistic that is resistant to outliers

Question 20

Mean/Average

Answer 20

Sum from i = 1 to n of Xi all over n.

Xbar is NOT robust

Question 21

Median

Answer 21

M = X(n+1 / 2), n odd or X(n/2) + X(n/2 + 1), n even

* IS robust

Question 22

Mode

Answer 22

Most frequent value

Question 23

Mid Point

Answer 23

(Min + Max) / 2

Question 24

Are Robust

Answer 24

M, Mode, IQR

Question 25

Not Robust

Answer 25

Mean, Range, S, S^2

Question 26

Measures of Spread

Answer 26

• Range
• Sample Variance
• Sample Standard Deviation
• IQR

Question 27

Range

Answer 27

R = X(n) - X(1)
R = Max - Min

Question 28

Sample Variance (s^2)

Answer 28

s^2 = 1/n-1 (Sum i=1 to n of (Xi - Avg)^2)

Question 29

Sample Standard Deviation (s)

Answer 29

Sqrt(s^2)

Question 30

IQR - Inner Quartile Range

Answer 30

IQR = Q3 - Q1

Question 31

Data Summaries

Answer 31

Mean and s –> Symmetric Bell Curve

Question 32

5 # Summary

Answer 32

X(1), Q1, M, Q3, X(n) –> skewed

Question 33

Outlier Detection Methods

Answer 33

Method 1: Any point outside Mean+- 3(s)

Method 2: Any point > Q3+1.5(IQR) or

Question 34

Box and Whiskers Plot

Answer 34

5 # Summary left to right just as you’d think