The EPA has set the safe drinking water limit for copper at 1.3 milligrams per liter (mg/L). In your sample, the mean copper content is 1.36 mg/L with a standard deviation of 0.18 mg/L from 30 randomly selected locations.
To determine if the new water source meets the EPA's standard, you should perform a hypothesis test using the provided sample data. The null hypothesis (H0) would be that the mean copper content is less than or equal to 1.3 mg/L, while the alternative hypothesis (H1) is that the mean copper content is greater than 1.3 mg/L.
With the given sample size, mean, and standard deviation, you can calculate the test statistic and compare it to a critical value to determine whether to accept or reject the null hypothesis. If the test statistic is greater than the critical value, you would reject the null hypothesis and conclude that the mean copper content of the new water source exceeds the EPA's safe limit.
It's important to remember that statistical tests can only provide evidence for or against a hypothesis, but cannot definitively prove that the new water source is safe or unsafe. Additional testing and monitoring would be necessary to make a well-informed decision about the safety of the water source.
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The minute hand takes 5 minutes to make 1/6 of half a rotation.
To determine the number of minutes it takes for a hand to make 1/6 of half a rotation, we first need to understand how many degrees are in a complete rotation. A complete rotation is 360 degrees. Half of this is 180 degrees. Therefore, to find 1/6 of half a rotation, we divide 180 by 6, which gives us 30 degrees.
Now we know that the hand moves 30 degrees. In one revolution (or 360 degrees), the minute hand takes 60 minutes. Therefore, to find the number of minutes it takes to move 30 degrees, we set up a proportion:
360 degrees / 60 minutes = 30 degrees / x minutes
Cross-multiplying, we get:
360x = 30 * 60
360x = 1800
x = 1800 / 360
x = 5
So, it takes 5 minutes for the hand to make 1/6 of half a rotation.
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Answer:
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Explanation:
Let's find the slope of the table. This will tell us the rate of change.
m = slope
m = (y2-y1)/(x2-x1)
m = (25250 - 26375)/(2 - 1) .... I used the first two rows
m = -1125/1
m = -1125
The slope of -1125 means the plane's altitude is decreasing at a rate of 1125 feet per minute. This is the descent speed.
Since we're told the initial altitude was 27500 ft, this means b = 27500
This means y = mx+b turns into y = -1125x+27500
x is the number of minutes and y is the altitude at time x
As a way to check this, plug in various x values of the table. You should get corresponding y values that match the table. I'll let you do this part.
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Now plug in y = 16250 and solve for x
y = -1125x+27500
16250 = -1125x+27500
-1125x+27500 = 16250
-1125x = 16250-27500
-1125x = -11250
x = -11250/(-1125)
x = 10
It takes 10 minutes after the descent period has started, for the pilot to get to 16,250 ft.
Since the pilot was contacted at the x = 4 minute mark, this means 10-4 = 6 minutes is the duration needed for the pilot to go from 23,000 ft to 16,250 ft.