Answer:
99% confidence interval for the population average examination score is between a lower limit of 69.2872 and an upper limit of 82.7128.
Step-by-step explanation:
Confidence interval = mean +/- margin of error (E)
mean = 76
variance = 144
sd = sqrt(variance) = sqrt(144) = 12
n = 25
degree of freedom (df) = n - 1 = 25 - 1 = 24
confidence level (C) = 99% = 0.99
significance level = 1 - C = 1 - 0.99 = 0.01 = 1%
t-value corresponding to 24 df and 1% significance level is 2.797
E = t×sd/√n = 2.797×12/√25 = 6.7128
Lower limit = mean - E = 76 - 6.7128 = 69.2872
Upper limit = mean + E = 76 + 6.7128 = 82.7128
99% confidence interval is (69.2872, 82.7128)
x = 9
Since M is the midpoint of XY:
XM = MY
XM = 2x + 11
MY = 5x - 16
2x + 11 = 5x - 16
5x - 2x = 11 + 16
3x = 27
x = 27/3
x = 8
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Answer: Circle
Solve for area
A≈86.66in²
C Circumference
Using the formulas
A=πr2
C=2πr
Solving forA
A=C2
4π=332
4·π≈86.65987in²
Step-by-step explanation: