Practice30Create account

Scores out of 45 of 50 competitors in an inter-school quiz, grouped with a class width of 9:
0-9: 6, 9-18: 10, 18-27: 16, 27-36: 12, 36-45: 6.
Using the step-deviation method with a = 22.5, find the mean score.

Class 10Mean of Grouped DataStatistics and Probability
  • A22.54
  • B22.14
  • C22.86
  • D26.1

Step-by-Step Solution

Class marks 4.5, 13.5, 22.5, 31.5, 40.5 are half-integers, but still gives the clean integers -2, -1, 0, 1, 2. . Mean . "22.54" drops the factor ; "22.14" reverses the sign; "26.1" divides by 5 classes instead of by 50.
Answer: C) 22.86

Master this chapter in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Mean of Grouped Data practice questions

More Class 10 Mean of Grouped Data practice

A test was written by a class whose marks are grouped as 0-10: 5, 10-20: 18, 20-30: 15,…A distribution is supplied as CLASS MARKS rather than as intervals: marks 8, 14, 20, 26,…For the distribution 25-35: 6, 35-45: 10, 45-55: 12, 55-65: 8, 65-75: 4 with a = 50 and…Copies of a newspaper sold per day by 100 vendors of a district: 0-100: 12, 100-200: 22,…In a grouped frequency table, what does the symbol 'fi' represent?