5/7 because it is greater than 1/4
C=2(pi)r use this equation with 9 in place of r
Answer:
90% confidence interval for the population mean is between a lower limit of $92.18 and an upper limit of $107.82.
Step-by-step explanation:
Confidence interval for a population mean is given as mean +/- margin of error (E)
mean = $100
sd = $25.20
n = 30
degree of freedom = n-1 = 30-1 = 29
confidence level (C) = 90% = 0.9
significance level = 1 - C = 1 - 0.9 = 0.1 = 10%
critical value (t) corresponding to 29 degrees of freedom and 10% significance level is 1.699
E = t×sd/√n = 1.699×25.20/√30 = $7.82
Lower limit of population mean = mean - E = 100 - 7.82 = $92.18
Upper limit of population mean = mean + E = 100 + 7.82 = $107.82
90% confidence interval is ($92.18, $107.82)
If you sketch the triangle, you need to understand that 12 is the length of opposite side (opposite to theta). Then the longest side is 13 is the hypotenuse. The other side with length 5 is the adjacent side. Thus from the definition of sin(theta)=opposite side/hypotenuse=12/13. A question for you, what is cos(theta)? cos(theta)=5/15 and tan(theta)=12/5
I believe it would be (b) (-2,1)
