Answer:
The center is (-3,2) and the radius is r=2
Step-by-step explanation:
The general equation of the given circle is
Add the square of half the coefficient of the linear terms to both sides of the equation to obtain;
The quadratic trinomials in x and y on the left side of the equations are perfect squares.
We factor to obtain;
Comparing to:
The center is (-3,2) and the radius is r=2
Let be the population mean lifetime of circulated $1 bills.
By considering the given information , we have :-
Since the alternative hypotheses is two tailed so the test is a two tailed test.
We assume that the lifetime of circulated $1 bills is normally distributed.
Given : Sample size : n=50 , which is greater than 30 .
It means the sample is large so we use z-test.
Sample mean :
Standard deviation :
Test statistic for population mean :-
The p-value=
Since the p-value (0.0433834) is greater than the significance level (0.02) , so we do not reject the null hypothesis.
Hence, we conclude that we do not have enough evidence to support the alternative hypothesis that the average lifetime of a circulated $1 bill differs from 18 months.