Question

solutions are there but i don't undestand why

4. The density histogram below shows the suicide rates for 200 different countries in the year 2010. Please answer the questions below about this histogram. (2 points each) (6%) Density (% of countries per 1 unit of rate) (496) (196) Jo 10 15 20 Suicide Rate (a) What percentage of countries had a suicide rate less than 12? 16%+48% 64% (b) What percentage of countries had a suicide rate between 0 and 4? 4%*4-16% (c) There were more countries with a suicide rate between 20 and 34 than there were countries with a suicide rate between 4 and 12. True False (14% vs 48%) (d) The histogram is incomplete because the bar for the interval between 15 and 20 is missing. a. What is the area of this missing bar? 100%-16%-48%-12%-14%-10% b. What is the height of this missing bar? 10%/5=2%

Answer 1

4)

The total area covered by all the bars in the histogram should equal 1

From the histogram, for suicide rates 0 to 4 the density is 4% per suicide

For suicide rates 4 to 12 the density is 6% per suicide

For suicide rates 12 to 15 the density is 4% per suicide

For suicide rates 20 to 34 the density is 1% per suicide

(a)

The percentage of countries = Density per suicide for 0 to 4 suicide rates * (4 - 0) + Density per suicide for 4 to 12 suicide rates * (12 - 4)

= 4% * 4 + 6% * 8 = 64%

(b)

The required percentage of countries = Density per suicide for 0 to 4 suicide rates * (4 - 0) = 4% * 4 = 16%

(c)

Percentage of countries with suicide rate between 4 and 12

= 6%*(12 - 4) = 48%

Percentage of countries with suicide rate between 20 and 34

= 1%*(34 - 20) = 14%

Thus, the statement is false

(d)

a. The area of the missing bar = 100% - (4%*4 + 6%*8 + 4%*3 + 1%*14)

= 10%

b. The height of the missing bar = 10%/(20 - 15) = 2%

3)

Similar to 4,

Area of the bar from Wages ranging from $500 to $700

= 100% - (10%*1 + 15%*1 + 5%*3 + 10%*3) = 30%

Thus, height of the bar = 30%/(7 - 5) = 15