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)
No real solutions, because for all real numbers the square of number is greater or equal 0.
Answer: 8
Step-by-step explanation:
Let the number be represented by x.
Two less than three times a number is the same as six more than twice the number. This will be:
(3 × x) - 2 = (2 × x) + 6
3x - 2 = 2x + 6
Collect like terms.
3x - 2x = 6 + 2
x = 8.
The number is 8
1.) <1=25°, <2=155°, <4=155°
Answer:
The answer is B. 
Step-by-step explanation:
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