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)
It is 800 because the 4 can not tell the what to do so that it is
Check the picture below. You can pretty much just count the units off the grid.
Explanation:
Starting with the first option, the square root of 12 and 8 isn’t a perfect square so it definitely can’t be reduced to 3/2.
It is the same for the second option as well.
Third option :
Root of 36 is 6
Root of 16 is 4
6/4 = 3/2
Fourth option:
Root of 81 is 9
Root of 36 is 6
9/6 = 3/2
Answer:
Therefore, the third and fourth options are the correct choices.
Hope this helped!
3 squares = 4 circles, so (number of squares)/(number of circles) = 3/4.
3/4 = 12/16
:::::
4 squares = 2 circles, so (number of squares)/(number of circles) = 4/2.
4/2 = 2/1
:::::
2 squares = 5 circles, so (number of squares)/(number of circles) = 2/5.
2/5 = 4/10