Answer:
a) To determine the minimum sample size we need to use the formula shown in the picture 1.
E is the margin of error, which is the distance from the limits to the middle (the mean) of the confidence interval. This means that we have to divide the range of the interval by 2 to find this distance.
E = 0.5/2 = 0.25
Now we apply the formula
n = (1.645*0.80/0.25)^2 = 27.7 = 28
The minimum sample size would be 28.
b) To answer the question we are going to make a 90% confidence interval. The formula is:
(μ - E, μ + E)
μ is the mean which is 127. The formula for E is shown in the picture.
E = 0.80*1.645/√8 = 0.47
(126.5, 127.5)
This means that the true mean is going to be contained in this interval 90% of the time. This is why it doesn't seem possible that the population mean is exactly 128.
Answer:
Step-by-step explanation:
Let us represent:
Number of children = x = 59
Number of Adults = y = 166
On a certain hot summer's day, 225 people used the public swimming pool.
x + y = 225
x = 225 - y
The daily prices are $1.75 for children and $2.00 for adults. The receipts for admission totaled $435.25.
$1.75 × x + $2.00 × y = $435.25
1.75x + 2y = 435.25
We substitute 225 - y for x
Hence:
1.75(225 - y ) + 2y = 435.25
393.75 - 1.75y + 2y = 435.25
Collect like terms
-1.75y + 2y = 435.25 - 393.75
0.25y = 41.5
y = 41.5/0.25
y = 166 Adults
Note that:
x = 225 - y
x = 225 - 166
x = 59 children
Hence, the number of children is 59 and the number of Adults is 166
Answer:
Step-by-step explanation:
Area = 28 Sq.ft
length * width = 28
2 * n = 28
Divide both sides by 2
2n/2 = 28/2
n = 14 ft