the answer should be A because the sea level has rised
Answer:
The standard error of the mean is 4.5.
Step-by-step explanation:
As we don't know the standard deviation of the population, we can estimate the standard error of the mean from the standard deviation of the sample as:
The sample is [30mins, 40 mins, 60 mins, 80 mins, 20 mins, 85 mins]. The size of the sample is n=6.
The mean of the sample is:
The standard deviation of the sample is calculated as:
Then, we can calculate the standard error of the mean as:
Answer:
The solution is x=4.75 and y = -22
Step-by-step explanation:
To find the solution to the system of equations, we will follow the steps below:
3.2x + 0.5y = 4.2 --------------------------------------------------------------------------(1)
-1.6x -0.5y = 3.4 ----------------------------------------------------------------------------(2)
add equation (1) and equation (2)
1.6x =7.6
Divide both-side of the equation by 1.6 to get the value of x
1.6x /1.6 =7.6/1.6
x =4.75
substitute x = 4.75 into equation (1) and solve for y
3.2(4.75) + 0.5y = 4.2
15.2 + 0.5y = 4.2
subtract 15.2 from both-side of the equation
15.2 - 15.2 + 0.5y = 4.2-15.2
0.5y = -11
Divide both-side of the equation by 0.5
0.5y/0.5 = -11/0.5
y = -22
The solution is x=4.75 and y = -22