Answer:
For this case we know that the confidence level is 90% so then the significance level is 
and 
. And we can find in the normal standard distribution a value who accumulates 0.5 of the area on each tail and we got:
And the best option would be:
1.645
Step-by-step explanation:
We assume that the parameter of interest is 
and we can assume that the distribution for this parameter is normally distributed so then the confidence interval assuming a two sided interval is given by:
Where 
represent the estimator for the parameter, SE the standard error and 
the critical value.
For this case we know that the confidence level is 90% so then the significance level is and . And we can find in the normal standard distribution a value who accumulates 0.5 of the area on each tail and we got:
And the best option would be:
1.645
-x+y=2
y=2+x
2+x=56x+1
x=56x-1
-55x=-1
x=0.181
Answer:
The width is 20 ft and the length is 80 ft
Step-by-step explanation:
Area = l * w
l = w +60
SA = 1600 ft^2 ( which is the regular area) The surface area of the water is just what is on top which is length times width
1600 = l*w
Substitute in l = w+60
1600 = (w+60) *w
Distribute the w
1600 = w^2 +60w
Subtract 1600 from each side
1600-1600 = w^2 + 60w -1600
0 = w^2 + 60w -1600
Factor
0=(w-20) (w+80)
Using the zero product property
w-20=0 w+80 =0
w=20 or w=-80
The width cannot be negative so
w=20
Now we need to find the length
l = w+60
l = 60+20
l =80
