Homework 7 Statistics 1192016 1 Histogram In a Public Health

Homework 7: Statistics (11/9/2016) 1. (Histogram) In a Public Health Service study, a histogram was plotted showing the number of cigarettes per day smoked by each subject (male current smokers), as shown below. The density is marked in parentheses. The class intervals include the right endpoint, not the left. (a) The percentage who smoked 10 cigarettes or less per day is around 1.5% 15% 30% 50% (b) The percentage who smoked more than a pack a day, but not more than 2 packs, is around 1.5% 30% 50% 15% There are 20 cigarettes in a pack) 15% (c) The percent who smaked more than a pack a day is around 1.5% 30% 50% (d) The percent who smoked more than 3 packs a day is around 0,5 of 1% 10% (e) The percent who smoked 15 cigarettes per day is around 3.5% 0.25 of 1% 0.35 of 1% 0.5 of 1% 1.5% 10% (3.5) 1.5) O.5) 0 10 20 40 80 Number of cigarettes 2. (Average and Standard Deviation) (a) Find the average and SD of the list 41, 48, 50, 50, 54, 57 (b) Which numbers on the list are within 0.5 SDs of average? within 1.5 SDs of average?

Solution

1. (a) The percentage who smoked 10 cigarattes or less per day is around 1.5%

1. (b) The percentage who smoke more than a pack a day but not more than 2 packs a day is around

(that is percentage who smoke between 20 to 40 cigarattes) = 1.5%

1. (c) The percenta ge who smoked more than a pack a day =

( that is percentage who smoke more than 20 cigarattes) = (1.5+0.5 =2% or) about 1.5%

1. (d) The percentage who smoked more than 3 pack a day =

   ( that is percentage who smoke more than 60 cigarattes) = about 0.5 of the 0.5% ( half of more than 40 less than 80) = 0.25 of 1%

1. (e) The percentage who smoked 15 cigarattes per day = around 3.5%