To know how far your values differ apart from the mean of the records
You can set it up like:
400/2.5 = 600/x; now cross multiply
400x = 2.5(600)
400x = 1,500; now divide both sides by 400 to isolate the x, and you get x = 3.75 hours
Answer:
b) equals 20 hours.
Step-by-step explanation:
The sampling distribution of means refers to the distribution of all the possible sample means, with a certain sample size (in this case, n=100) extracted from the population.
The sampling distribution of the means is equal to the population mean. That does not mean that every sample will result in a mean equal to the population, but that the population of sample means will have an average of 20 hours.
99.7%, according to the rule.