The lifetimes (in hours) of 80 LED bulbs are grouped as: 300-400: 10, 400-500: 12, 500-600: 18, 600-700: 20, 700-800: 11, 800-900: 6, 900-1000: 3. Using the step-deviation method (a = 650, h = 100), find the mean lifetime (in hours).

Question

Accepted Answer

600. Class marks: 350,450,550,650,750,850,950. ui = -3,-2,-1,0,1,2,3. fi*ui = 10*-3+12*-2+18*-1+20*0+11*1+6*2+3*3 = -30-24-18+0+11+12+9 = -40. sum fi = 80. Mean = 650 + 100*-40/80 = 650 - 50 = 600.

The lifetimes (in hours) of 80 LED bulbs are grouped as:
300-400: 10, 400-500: 12, 500-600: 18, 600-700: 20, 700-800: 11, 800-900: 6, 900-1000: 3.
Using the step-deviation method (a = 650, h = 100), find the mean lifetime (in hours).

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 Mean of Grouped Data practice

The lifetimes (in hours) of 80 LED bulbs are grouped as:300-400: 10, 400-500: 12, 500-600: 18, 600-700: 20, 700-800: 11, 800-900: 6, 900-1000: 3.Using the step-deviation method (a = 650, h = 100), find the mean lifetime (in hours).

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 Mean of Grouped Data practice

The lifetimes (in hours) of 80 LED bulbs are grouped as:
300-400: 10, 400-500: 12, 500-600: 18, 600-700: 20, 700-800: 11, 800-900: 6, 900-1000: 3.
Using the step-deviation method (a = 650, h = 100), find the mean lifetime (in hours).