Module 2 - Graphs & 'Modal' Distributuions

Question 1

What are the 3 types of graphs used in this class?

Answer 1

1. Bar Chart
2. Histograms
3. Boxplots

Question 2

Bar Charts (4)

Answer 2

leave space bw bars

Question 3

When should a bar graph be used?
Why is it helpful?

Answer 3

• Should be used for nominal and ordinal with categories variables
• It can be expressed in percentage of the total
• Detects patterns and data entry errors

Question 4

Histograms

Answer 4

Example:
- there are 14 people bw 85-89
- 1 person bw 75-79

Question 5

When should a histogram be used?
Why is it helpful?

Answer 5

• Should be used for interval and ratio variables
• It offers similar information to the steam and leaf table
• Useful for describing a variable’s distribution and detect data entry errors

Question 6

Histogram relationship bw stem and leaf table

Answer 6

Question 7

What is a Boxplot?
What are its 7 Main components?

Answer 7

1) Median of the distribution (aka, 50th percentile)
2) Lower quartile (aka, 25th percentile)
3) Upper quartile (aka, 75th percentile)

4) Minimum non-extreme score
5) Maximum non-extreme score

6) Lower bound outlier
7) Upper bound outlie

Question 8

When should a box plot be used?
Why is it helpful?

Answer 8

• Should be used for interval and ratio variables
• It can help identifying outliers and data entry errors
• Useful for describing a variable’s distribution

Question 9

What 11 statistcs are observed when collecting data

Answer 9

1. Valid scores
2. Missing scores
3. Mean (aka average)
4. Median (aka 50th percentile)
5. Mode
6. Standard deviation
7. Quartiles (Lower and Upper)
   (aka 25th and 75th percentiles)
8. Minimum
9. Maximum
10. Skewness
11. Kurtosis

Question 10

When should statistics be used?
Why are they helpful?

Answer 10

• Should be used for interval and ratio variables
• Help identifying missing data, data entry errors, outliers, and describe the data distribution

Question 11

What are the 3 characteristics used when describing distributions?

Answer 11

1. Modality
2. Symmetry
3. Variability

Question 12

What is a Unimodal Distribution

Answer 12

• 1 Peak
• AKA Normal Distribution
• “Bell Curve”

Question 13

What is Bimodal DIstribution?

Answer 13

• 2 peaks
• Must consist of a valid “Valley”

Question 14

What is Multimodal Distribution?

Answer 14

• 3+ Peaks

Question 15

What tools help us determine the modality of a data set?

Answer 15

Histogram + Density Plot

note: there is no valid valley in the distribution