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)
-27+8
( The minus signs multiply each other to form a +. )
= -19
Answer:
The 1st graph will be perfectly matching the conditions.
Step-by-step explanation:
A wholesaler requires a minimum of 4 items in each order from its retail customers.
The manager of one retail store is considering ordering a certain number of sofas, x and a certain number of pillows that come in pairs, y.
Therefore, for y = 0, x ≥ 4 and for x = 0, y ≥ 2 to make the order of 4 items or more.
Therefore, the equation for the order to be of 4 items will be
x + 2y = 4.
So, the 1st graph will be perfectly matching the conditions. (Answer)
Answer
given,
work = 5 J
spring stretch form 30 cm to 39 cm

x = 0.39 - 0.30 = 0.09 m


k = 1234.568 N/m
a) work when spring is stretched from 32 cm to 34 cm
x₂= 0.34 -0.30 = 0.04 m
x₁ = 0.32 - 0.30 = 0.02


W = 0.741 J
b) F = k x
25 = 1234.568 × x
x = 0.0205 m
x = 2.05 cm