) If the standard deviation of a random variable X is 15 and a random sample of size n=15 is obtained, what is the standard deviation of the sampling distribution of the sample mean?

3.8731

Step-by-step explanation:

The standard deviation of the sampling distribution of the sample mean is also called the standard error of the mean expressed as;

SM = s/√n

s is the standard deviation of the random variable X

n is the sample size

Given

s = 15

n = 15

Required

Standard deviation of the sampling distribution of the sample mean.

Substituting the given parameters into the expression above;

SM = 15/√15

SM = 15/3.8729

SM = 3.8731

Hence the standard deviation of the sampling distribution of the sample mean is 3.8731

1/3 + 1/3 ≠ 2/6 because 1/3 alone = 2/6  

step by step explanation:

1/3 + 1/3 = 2/3       2/3=4/6

he earned 78.75 in interest.

step-by-step explanation: