Answer:
The standard error of the mean = 5.14 mins
Step-by-step explanation:
Number of random sample (n) = 20
Mean(X) = 31.25 mins
Standard deviation (α) = 23.7 mins
Standard error of mean =
standard deviation / √sample size
= 23.7/√20
= 23.7/4.4721
= 5.14 mins
I don't really know if the question is complete but...
y = x -10 can be a solution
so y would be -7 when x is 3
S = n(a1 + an)/2
2S = n(a1 + an)
2S = na1 + nan
nan = 2S - na1
an = (2S - n a1)/n
The answer, at least what I got, is 17.375 . They'd have to open an eighteenth package because the extra .375 is not in the original package, so I would go with B .
