The confidence interval formula is computed by:
Xbar ± Z s/ sqrt (n)
Where:
Xbar is the mean
Z is the z value
S is the standard deviation
N is the number of samples
So our given are:
90% confidence interval with a z value of 1.645
Sample size 40, 45
Mean 180, 179
Standard deviation 2, 4
So plugging that information in the data will give us a
confidence interval:
For 1:
Xbar ± Z s/ sqrt (n)
= 180 ± 1.645 (2 / sqrt (40))
= 180 ± 1.645 (0.316227766)
= 180 ± 0.520194675
= 179.48, 180.52
For 2:
Xbar ± Z s/ sqrt (n)
= 179 ± 1.645 (4 / sqrt (45))
<span>= 179 ± 1.645 (0.596284794)</span>
therefore, the answer is letter b
It is 31%.
To explain, you have to just have to multiply 0.31 by 100, and then add a percentage sign.
Answer:
531.167 ft²
Step-by-step explanation:
Given data
Dimension of pool
Diameter =24ft
Radius =12ft
If the cover must hang by 1ft around, then the diameter is 26ft
Radius =13ft
Area of cover = πr²
Substitute
Area = 3.142*13²
Area =3.143*169
Area =531.167 ft²
Hence the minimum area is 531.167 ft²
Option c would be correct
