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.
D. <span>F(x) = 7x − 105 because however many cars they wash and the amount of money they gain from it, they will still have a combined $105 to spend on the supplies and space.</span>
Answer:
pic?
Step-by-step explanation:
Suzette ran for 1.6 hours and biked for 2.4 hours.
Let x = total hours Suzette ran.
Let y = total hours Suzette biked.
The equation to solve the question will be:
x + y = 4 ...... i
6.5x + 14y = 44.75 ....... ii
From i, y = 4 - x
Put the value of y into equation ii
6.5x + 14y = 44.75
6.5x + 14(4 - x) = 44.75
6.5x + 56 - 14x = 44.75
Collect like terms
6.5x - 14x = 44.75 - 56
-7.5x = -11.25
x = 11.25/7.5
x = 1.6 hours
Since x + y = 4
1.6 + y = 4
y = 4 - 1.6
y = 2.4 hours.
Suzette ran for 1.6 hours and biked for 2.4 hours.
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