A random sample is made of 256 middle managers concerning their annual incomes. The sample mean is computed to be $35,420. If the population standard deviation is $2,050. What is the standard error of the mean?

a. $128.125
b. $138.36
c. $2.050
d. $8.01

Respuesta :

Answer: a. $128.125

Step-by-step explanation:

The standard error of the mean is given by :

[tex]SE=\dfrac{\sigma}{\sqrt{n}}[/tex] , where [tex]\sigma[/tex] = population standard deviation , n= sample size.

Given: [tex]\sigma=\$2,050[/tex]

n= 256

Then, the standard error of the mean:-

[tex]SE=\dfrac{2050}{\sqrt{256}}\\\\=\dfrac{2050}{16}=\$128.125[/tex]

Hence, option a. is correct.