Histograms Quiz

1. What is the formula for frequency density?

• A. frequency $\times$ class width
• B. frequency $\div$ class width
• C. class width $\div$ frequency
• D. frequency $+$ class width

2. A class $10<x\le30$ has frequency 50. What is its frequency density?

• A. $500$
• B. $25$
• C. $0.4$
• D. $2.5$

3. A bar has width 5 and height (frequency density) 3.2. What is the frequency of the class?

• A. $1.6$
• B. $8.2$
• C. $16$
• D. $0.64$

4. In a histogram with unequal class widths, what does the area of a bar represent?

• A. The frequency
• B. The frequency density
• C. The class width
• D. The mean

5. The class $10<x\le20$ has frequency 40, evenly spread. Estimate how many values lie in $10<x\le13$.

• A. $13$
• B. $12$
• C. $4$
• D. $10$