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:
8/100 + 8/100 + 32/100 = 48/100
48/100 / 4/4 = 12/25
Step-by-step explanation:
Answer: -2.5,, -0.9,, -1/3,, 1.7,, 27/4
Step-by-step explanation: