The thicknesses, kmm, of some steel sheets are represented in the histogram. It is given that k < 0.4 for 180 sheets.

a. Find the ratio between the frequencies of the three classes. Give your answer in simplified form.

b. Find the value of n, given that frequency density measures sheets per nmm.

c. Calculate an estimate of the number of sheets for which:

i. k < 0.5 

ii. 0.75 ≤ k < 0.94.

d. The sheets are classified as thin, medium or thick in the ratio 1: 3 :1.

Estimate the thickness of a medium sheet, giving your answer in the form a

Transcribed Image Text:

5 0.2 0.4 0.6 0.8 1.0 1.2 Thickness (k mm) 4. 2. Frequency density