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.
Answer:
x = - 2, x = 9
Step-by-step explanation:
Given
f(x) =
The denominator of f(x) cannot be zero as this would make f(x) undefined.
Equating the denominator to zero and solving gives the values that x cannot be.
x² - 7x - 18 = 0
(x - 9)(x + 2) = 0
Equate each factor to zero and solve for x
x + 2 = 0 ⇒ x = - 2
x - 9 = 0 ⇒ x = 9
The excluded values are x = - 2, x = 9