Question

Fire load (MJ/m) is the heat energy that could be released per square meter of floor area by combustion of contents and the structure itself. The following cumulative percentages are for fire loads in a sample of 388 rooms: Value 900 0 150 300 450 600 750 Cumulative % 19.0 86.5 93.1 0 37.4 62.2 76.9 Value 1950 1050 1200 1350 1500 1650 1800 Cumulative % 95.1 97.8 98.4 99.5 99.6 99.8 100.0 (a) Construct a relative frequency histogram. Relative Relative Frequency Frequency 0.25 0.15 0.20 0.10 0.15 0.10 0.05 0.05 Fire load Fire load 300 600 900 1200 1500 1800 300 600 900 1200 1500 1800 Relative Relative Frequency 0.20r Frequency 0.25 0.15 0.20 0.15 0.10 0.10 0.05 0.05 Fire load Fire load 300 600 900 1200 1500 1800 300 600 900 1200 1500 1800 Comment on interesting features. (Select all that apply.) The relative frequency distribution is symmetric. The relative frequency distribution exhibits a large negative skew. The relative frequency distribution exhibits a large positive skew The typical middle value is somewhere between 300 and 450. The typical middle value is somewhere between 150 and 300 (b) What proportion of fire loads are less than 600? At least 1200? (Round your answers to three decimal places.) less than 600 at least 1200o (c) what proportion of the loads are between 600 and 1200? (Round your answer to three decimal places.)

Answer 1

a) bottom right plot is correct

exhibits a large positve skew

typical middle value is somewhere between 300 and 450

b)

P(less than 600)=0.154

P(At least 1200)=0.049

c)

P(between 600 and 1200) =0.182 ( please try 0.356 if 600 and 1200 needs to be included)