In: Statistics and Probability
Students studying at GWU spend an
average of $172.50 per week on basic needs other than...
Students studying at GWU spend an
average of $172.50 per week on basic needs other than housing. Use
this figure as the population mean and assume that population
standard deviation is $75.00.
- What is the probability that the mean expenditure for a sample
of 35 students is within $20 of the population mean? What
assumption do you need to make for this calculation?
- What is the probability that the mean expenditure for a sample
of 50 students is within $20 of the population mean?
- What is the probability that the mean expenditure for a sample
of 70 students is within $20 of the population mean?
- Which, if any, of the samples sizes in parts (a), (b), and (c)
would you recommend in order to have at least a .95 probability
that the sample mean is within $20 of the population mean?
- Using the standard error in c), calculate the value of
x1, x2 such that P(x1 ≤ x ≤
x2) = .95 and express that result in terms of a range
around the original population mean of $172.50. Hint: Use the
conversion formula from z to x.