Question

please help me on this two questions. Thank you! i was not sure if 0 could also be a fixed number and what are other cases like?

1) If a fixed number, c, is added to all measurements in a numerical data set, what is the effect on the sample mean and the sample standard deviation? Justify your answer.

2)

For an article on the rising price of college textbooks, the student newspaper conducted a survey of 60 students to see how many textbooks with a price of $80 or more each was required to purchase. The results of the survey were as follows: 5. student # of books costing at least $80; # of students required to buy: 4 5 8 22187. Compute the sample mean, sample median and sample standard deviation for the number of books costing at least $80.

Answer 1

Adding a constant c to each value in a data set does not change the distance between values so the standard deviation remains the same. X' will change by x' + c

Sample mean = $\sum$fx/n

Sample sd = sqrt (( n $\sum$fx^2-($\sum$fx)^2) / n ( n-1) )