Answer:
$ 14
Step-by-step explanation:
$ 40 --- 100%
$ x --- 35%
x = 40*35/100 = 14
The reciprocal is -0.41176470588
<span>Leah, Let x=Blair's fish and 2x= Jay's fish; yet together they caught 27 fish. So, x + 2x=27; Combine the like terms. So, 3x=27; Now divide both sides of the equation by 3, therefore, x=9 which is the amt of fish Blair caught. So, 2(9)=18 is the amt of fish Jay caught. Check: 9 +2(9)=27; 27=27.</span>
Given Information:
Number of lithium batteries = n = 16
Mean life of lithium batteries = μ = 645 hours
Standard deviation of lithium batteries = σ = 31 hours
Confidence level = 95%
Required Information:
Confidence Interval = ?
Answer:

Step-by-step explanation:
The confidence interval is given by

Where μ is the mean life of lithium batteries, σ is the standard deviation, n is number of lithium batteries selected, and t is the critical value from the t-table with significance level of
tα/2 = (1 - 0.95) = 0.05/2 = 0.025
and the degree of freedom is
DoF = n - 1 = 16 - 1 = 15
The critical value (tα/2) at 15 DoF is equal to 2.131 (from the t-table)





Therefore, the 95% confidence interval is 628.5 to 661.5 hours
What does it mean?
It means that we are 95% confident that the mean life of 16 lithium batteries is within the interval of (628.5 to 661.5 hours)