Question

vThe mean starting salaries of a random sample of three students who graduated from college last year with majors in the mathematical sciences was $44,000 with standard error $5773.51 (Note: do not use $ symbols or commas in your answers.)

(a) What is the margin of error for a 95% confidence interval?  (Round to the nearest whole number.)


(b) Find the lower limit  and the upper limit  of the 95% confidence interval. (Round to the nearest whole number.)

(c) Other than decreasing the level of confidence, what else could be done to make the confidence interval in (b) narrower?

decrease the sample sizedecrease the population mean    increase the sample sizedecrease the sample mean

(d) Which of the two statements below must be reasonably true for the interval to be valid?

There are at least 15 successes and 15 failuresThe sample size is large.The sample was randomly selected.The population is approximately normal

Answer 1