Q8 of 33 Page 14

Find the value of p, if the mean of the following distribution is 20. 

x 15 17 19 20 + p 23
f 2 3 4 5p 6

 








xifixi fi
15230
17351
19476
20 + p5p100p + 5p2
236138
Total15 + 5p5p2+100p + 295

Mean = =
20 =
5p2+100p + 295 = 300 + 100p
            5p2 - 5 = 0
          5(p2 - 1) = 0
   (p + 1)(p - 1) = 0
       p = 1 or p = -1

More from this chapter

All 33 →
6 The median of the observations 11, 12, 14, 18, x + 2, x + 4, 30, 32, 35, 41 arranged in ascending order is 24. Find the value of x. 7 Find the median of the following data: 19, 25, 59, 48, 35, 31, 30, 32, 51. If 25 is replaced by 52 and 19 by 29, what will be the new median? 1

If the mean of the following data is 20.6. Find the value of p.

 2

Following are the lives in hours of 15 pieces of the components of aircraft engine. Find the median:

715, 724, 725, 710, 729, 745, 694, 699, 696, 712, 734, 728, 716, 705, 719