We have a sample of 28 data points. The sample mean is 30.0 and the sample standard deviation is 2.40. The confidence level required is 98%. Then, we calculate α by:
The confidence interval for the population mean, given the sample mean μ and the sample standard deviation σ, can be calculated as:
Where n is the sample size, and Z is the z-score for 1 - α/2. Using the known values:
Where (from tables):
Finally, the interval at 98% confidence level is:
Answer:
x = - 6 ±
Step-by-step explanation:
Given
x² + 12x = 1
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(6)x + 36 = 1 + 36
(x + 6)² = 37 ( take the square root of both sides )
x + 6 = ± ( subtract 6 from both sides )
x = - 6 ± ← exact solutions
Answer:
D
Step-by-step explanation:
The quadratic formula:
where a is the coefficient of , b being the coefficient of
and c being the constant.
Plug in the values:
Since
The answer is: