Two Samples Are Selected at Random from Two Independent Normally $\bar { X } _ { 1 } - \bar { X } _ { 2 }$

Multiple Choice

Two samples are selected at random from two independent normally distributed populations. Sample 1 has 49 observations and has a mean of 10 and a standard deviation of 5. Sample 2 has 36 observations and has a mean of 12 and a standard deviation of 3. The standard error of the sampling distribution of the sample mean difference, $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ , is:

A) 0.1853.
B) 0.7602.
C) 0.7331.
D) 0.8719.