Answer:
A one-sample t-interval for a population mean
Step-by-step explanation:
As the question is "How many minutes per day, on average, do you spend visiting social media sites?", the answer will be in a numerical form (number of hours, positive integer or real number).
As this is not a proportion, the option "A one-sample t-interval for a population mean" is discarded.
As the study does not defined another variable to compare in pairs, it is not a matched-pairs test. Option "A matched-pairs t -interval for a mean difference" discarded.
There are not two means in the study, so there is no "difference between means" variable. Options "A two-sample z-interval for a difference between proportions" and "A two-sample t-interval for a difference between means".
This should be a one-sample t-interval for a population mean, as there is only one sample, one population mean and the population standard deviation is not known.
The difference of finish times has a mean of
μ = 105 -98 = 7 . . . . minutes
and a variance of
σ² = 10² +15² = 325 . . . . minutes²
Using a probability calculator, we find the probability to be
p(-5 < x < 5) ≈ 0.2030
The expressions is undefined in the set of the real numbers.
40/12 = 100/x
Cross-multiply and get:
40x = 1200
Divide both sides by 40:
x = 30
It will take 30 minutes for the machine to weave 100 inches of fabric.
