Question

If first 15 observations are increased by 12 each and last 25 observations are decreased by 18 each and if original mean was 215 find new mean. ​

Answer 1

Answer:

208.25

Step-by-step explanation:

you have not mentioned total no of observations

so, I'm assuming it to be 15+25=40

first 15 observations increased by 12 each

=> sum of observations increases by 12×15=180

last 25 observations decreased by 18 each

=> sum observations decreased by 18×25=450

overall the sum is decreased by 450-180= 270

=> mean is decreased by 270/40 = 6.75

new mean =215-6.75= 208.25

hope this helps