Answer:
a)
Mean = sum of all numbers in dataset / total number in dataset
Mean = 8130/15 = 542
Median:
The median is also the number that is halfway into the set.
For median, we need to sort the data and then find the middle number which in our case is 546. Below is the sorted data
486 516 523 523 529 534 538 546 548 551 552 558 566 574 586
Standard Deviation (SD). Here X represents dataset and N= count of numbers in data
As per the SD formula, which is Sqrt ( sum (X_i - Meanx(X))/(N-1))
SD= 25.082
2) Formula for coefficient of skewness using Pearson's method (using median) is,
SK = 3* ( Mean (X) - Median(X))/(Standard Deviation) = 3*(542-546)/25.082 = -0.325
3) coefficient of skewness using the software method is also same which is -0.325
Multiply 75*5 to get 375
then add 120 from the lot to get 495
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The answer is D.137
The questions asked how many people he surveyed therefore you are to add up all the numbers.
74+33+12+18= 137
