Hi,
Work:
Equation;

Factor out 2x from expression.

Use commutative property to reorder yc.

Hope this helps.
r3t40
Answer:
Step-by-step explanation:
Data given and notation
represent the sample mean given
represent the population standard deviation
sample size
represent the value that we want to test
t would represent the statistic (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the true mean for the gasoline prices is lower than 1.25, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
If we analyze the size for the sample is > 30 but we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:
(1)
Calculate the statistic
We can replace in formula (1) the info given like this:
Answer:
87.92 in²
Step-by-step explanation:
pi × (R² - r²) = area
Where R is the radius of the outer circle and r of the inner circle.
Since C = 2pi×r
37.68 = 2×3.14×r
r = 6 in
R = 6 + 2 = 8 in
Therefore,
pi × (R² - r²) = area
Area = 3.14 (8² - 6²)
= 87.92 in²