class IX statics

                                                                Class IX-Mathematics

                                                               Statistics  (HOTS)

1.Mean of the ten observations x1, x2, .... X10 is p. If each of the first five observations is increased by

   5 and each of the next five observations is decreased by 5 then new mean is q. Find p - q. 

2.  If M =4+X2+.X5/15 , then find the value of x1 -M/15 +  x2-M/15  +  x3 -M/15 +......+X15-M/15.

3.Find the length of the longest rod that can be placed in a room 30 m long, 24 m broad and 18 m high.

4.A man spends ₹1,800 monthly on an average for the first four months and ₹2,000 monthly for the

   next eight months and saves ₹5,600 in a year. Find his average monthly salary.

5.The mean of 25 observations is 18. The mean of first twelve of them is 14 and that of last

   twelve is 17. Find the thirteenth result.

6.In a cricket team, the average age of eleven players is 28 years. Out of these, the mean ages of three

  groups of three players each are 25 years, 28 years and 30 years respectively. If in these groups the

  captain and the youngest player are not included, and the captain is eleven years older than the

  youngest player, what is the age of the captain?

7.A team of 8 persons joins in a shooting competition. The best marksman scored 85 points. If he had

  scored 92 points., the average score for the team would have been 87. Find the total number of

   points scored by the team.