The population standard deviation of the numbers 3, 8, 12, 17, and 25 is 7.563 correct to 3 decimal places. what happens if each of the five numbers is multiplied by 3
Accepted Solution
A:
Let's figure this out as though we have no idea what the answer would be.
Step One Find the new five numbers. 3*3, 8*3, 12*3, 17*3, 25*3 9 , 24 , 36, 51, 75
Step 2 Find the average (9 + 24 + 36 + 51 + 75)/5 = 195/5 = 39
Step 3 Subtract the individual numbers from the average (39 - 9) = 30 (39 -24) = 15 (39 - 36) = 3 (39 - 51) = - 12 (39 - 75) = -36
Step 5 Take the average of the results from step 4 (900 + 225 + 9 + 144 + 1296)/5 2574 / 5 = 514.8
Step 6 Take the square root of the result from step 5 deviation = sqrt(514.8) deviation = 22.689
Step seven Compare the two standard deviations. s2/s1 = 22.689 / 7.563 = 3
Conclusion If you are given 1 set of numbers to find a population standard deviation and you multiply each member by a, then the result will be a * the standard population deviation of the first set of numbers.
Note Your calculator will do this as well, but you have to know how to enter the data into your calculator. That requires that you follow the directions carefully.