Complete question:
The manager of a supermarket would like to determine the amount of time that customers wait in a check-out line. He randomly selects 45 customers and records the amount of time from the moment they stand in the back of a line until the moment the cashier scans their first item. He calculates the mean and standard deviation of this sample to be barx = 4.2 minutes and s = 2.0 minutes. If appropriate, find a 90% confidence interval for the true mean time (in minutes) that customers at this supermarket wait in a check-out line
Answer:
(3.699, 4.701)
Step-by-step explanation:
Given:
Sample size, n = 45
Sample mean, x' = 4.2
Standard deviation
= 2.0
Required:
Find a 90% CI for true mean time
First find standard error using the formula:




Standard error = 0.298
Degrees of freedom, df = n - 1 = 45 - 1 = 44
To find t at 90% CI,df = 44:
Level of Significance α= 100% - 90% = 10% = 0.10

Find margin of error using the formula:
M.E = S.E * t
M.E = 0.298 * 1.6802
M.E = 0.500938 ≈ 0.5009
Margin of error = 0.5009
Thus, 90% CI = sample mean ± Margin of error
Lower limit = 4.2 - 0.5009 = 3.699
Upper limit = 4.2 + 0.5009 = 4.7009 ≈ 4.701
Confidence Interval = (3.699, 4.701)
With these transversals across parallel lines the angles are either congruent or supplementary (adding to 180) and its pretty easy to figure out which is which, obtuse verse acute in the figure.
Each yellow circle indicates x and the path to the next square. So for example the Start has alternate interior angles, which are congruent, so x is 141 degrees.
Answer:
(64,86.5)
Step-by-step explanation:
find the case where he gets 70 and the case where he gets 79
if his average is 70:
(75+62+85+2x)/5=70
(222+2x)/5=70
222+2x=350
2x=128
x=64
if his average is 79:
(75+62+85+2x)/5=79
(222+2x)/5=79
222+2x=395
222+2x=395
2x=173
x=86.5
Answer:
No Solution.
Step-by-step explanation:
-(6x-5)=-6x+13
-6x+5=-6x+13
-6x-(-6x)+5=13
-6x+6x+5=13
0+5=13
5=13
Answer:
im having the same problem,
Step-by-step explanation:
maybe search it up on google and see what comes up