Answer:
Standard error
Step-by-step explanation:
The standard deviation of the distribution of sample means is called the standard error of the means.
It is denoted by: 
The standard error is calculated using the formula: 
where n is the sample size and 
is the population standard deviation.
This is the answer step by step
Answer: Use order of operations (PEMDAS). Answer is 45.72.
Step-by-step explanation:
First, solve inside parenthesis:
(5.25*1 1/5 - 4.5*4/5)
Convert 1 1/5 into decimal. It will be easier. 1 1/5 is the same as 1.2
Do multiplication and division first.
5.25*1.2 = 6.3
Now it looks like: (6.3 - 4.5*4/5)
Convert 4/5 to a decimal: 4/5 = 0.8
(6.3 - 4.5*0.8)
Multiply 4.5*0.8 = 3.7
Subtract (6.3 - 3.7) = 2.6
Now the full equation is: 19.6*2 1/5 + (2.6)
2 1/5 as a decimal: 2.2
Multiply 19.6*2.2 = 43.12
Now the equation is: 43.12 + 2.6
Add 43.12 + 2.6 = 45.72
The answer is C
By the way, that expression means "n choose k". Hope I helped!
