Question

A population has a mean of 161.2 and a standard deviation of 9.6. A sample of size 13 is taken from this population. What is the standard deviation of the sampling distribution of the mean?  Enter your answer to 3 decimal places.

We have two random variables, A and B. A has a mean of 74.6 and a standard deviation of 36.4. B has a mean of 35.7 and a standard deviation of 19.4. If we create a new random variable C, defined as C= A + B, what is the mean of C? Enter your answer as a decimal to one decimal place.

Answer 1

Solution :

1) mean = = 161.2

standard deviation = = 9.6

n = 13

=   = 161.2

= / n = 9.6 / 13  = 2.663

2) mean = A = 74.6

standard deviation = A = 36.4

mean = B = 35.7

standard deviation = B = 19.4

C =  A + B

C = 74.6 + 35.7 = 110.3