Answer:
99
Step-by-step explanation:
First give it as a product of prime factors. Divide 9801 with prime numbers. The first picture divides 9801 fron prime numbers. Prime numbers are 2,3,5,7, 11. We can only divide using 3 and 11. So we get 3⁴ and 11². The second picture shows how I got the square root of 9801. Square root is ½. So we multiply each power with ½ so we finally get 99. You can recheck for yourself using a calculator. It is 99.
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)