The following data is the results of a random sample of the ages (in years) of 12 houses in a community: 18, 22, 23, 19, 18, 24, 26, 20, 17, 12, 27, 28. Assume the population is normal.
Construct a 90% confidence interval for the mean age of a house in this community.
a) (18.8, 23.5) b) (18.7, 23.6) c) (18.9, 23.4) d) (19.0, 23.3)
7. If you want to estimate the mean age of a house in the community discussed in question 5 within 1.5 years with 98% confidence, how many houses should be included in the sample? Assume = 4.9 years.
a) 7 b) 58 c) 79 d) 8
If 17 out of 500 students are math majors, what is the value point estimate for the proportion of the students who are mathematics majors?
a) 34% b) 8.5% c) 3.4% d) 29.4%