Applied Statistics - 3.4 - Histograms

Question 1

What is a Histogram?

Answer 1

Chart where area of the bar is proportional to the frequency in each class

Question 2

Area of bar, Frequency Density

Histogram Equations

Answer 2

• Area of bar = frequency density * class width
• Frequency density = frequency / class width

Question 3

How to form a frequency polygon from a Histogram?

Answer 3

Join the middle of the top of each bar in the histogram to form a frequency polygon

Question 4

Frequency polgygons - How to calculate mean

Answer 4

(Midpoint of group * (group width * frequency density)) / Number of objects

Question 5

What does Positively/Negatively skews mean?

Answer 5

• High peak at lower values of x
• High peak at high values of x

Question 6

How to compare data?

Answer 6

Comment on:
- Interquartile range (less range = more precise)
- Median
(On average has a higher/lower____)
-Outliers
-Positively/Negatively skewed

Question 7

Strong vs Weak correlation

Answer 7

• Strong correlation means values are close to line of best fit
• Weak correlation means values are not all close to line of best fit