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)
Answer:
So a bag of chip costs $2.39
Step-by-step explanation:
Let x = cost of a bag of chip
Let y = cost of a box of pretzel
Micheal buys two bags of chips and three boxes of pretzels for $5.13
This means
2x + 3y = 5.13 - - - - - - - - - -1
He then buys another bag of chips and 2 boxes of pretzels for $3.09
This means
x + 2y = 3.09 - - - - - - - - - - - -2
Solving equation 1 and equation 2 simultaneously and using the elimination method,
Multiply equation 1 by 1 and equation 2 by 2
2x + 3y = 5.13
2x + 6y = 6.18
Subtracting,
-3y = -1.05
y = -1.05/-3= $0.35
Put y= 0.35 in equation, x + 2y = 3.09
x + 2(0.35)= 3.09
x + 0.7= 3.09
x = 3.09-0.7 = $ 2.39
So a bag of chip costs $2.39
Write and solve an equation:
Total earnings = $782.75 = s(40 hrs) + 1.5*s*(7 hrs)
Then 782.75 = 40s + 10.5s = 50.5s
Dividing both sides by 50.5: s = 15.5. The attendant's regular hourly wage was $15.50.
Do you have any pictures?
Answer:
(-6, 0)
Step-by-step explanation:
y = 4x + 24
Plug y = 0
0 = 4x + 24
4x = - 24
x = - 24/4
x = - 6
So, the graph of y = 4x + 24 intersect the x-axis at (-6, 0)
