Answer: A~ 45
Step-by-step explanation:
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:
area = 202.5 yd²
Step-by-step explanation:
area = (15 x 12 ) + (3)(15)(0.5)
area = 180 + 22.5 = 202.5 yd²
3 3/4 divided by 1/2 is 7 1/2.