1st Exam equations

Question 1

mean

Answer 1

( x1 + x2 + x3 + . . . + xN) / N

Question 2

deviation from the mean of data point

Answer 2

xi - mean

Question 3

standard deviation

Answer 3

s = Square root ( xi - mean )^2 / N-1

Question 4

Deviation of mean

Answer 4

S = s / square root of N

Question 5

RSD (relative SD) & CV (coefficient of variation)

Answer 5

RSD/CV = s / mean x 1000 or 100%

Question 6

Range

Answer 6

w = highest value - lowest value

Question 7

Spooled

Answer 7

square root of ( xi - mean ) ^2 + … / N[DATA POINTS] + N[DATA POINTS] - NO. OF SETS

Question 8

Confidence Interval

Answer 8

mean +- ts / square root of N (where t is the confidence level & N-1

Question 9

Q-test

Answer 9

xq-xn / w (xq is rejected if Qexp >= Qcritical

Question 10

Least - Square Method

Answer 10

y = mx + b

Question 11

Absolute error

Answer 11

xi - xt

Question 12

Relative error

Answer 12

Er = xi - xt / xt X 100% or 1000 if ppt