Question

The starting salaries of a random sample of three students who graduated from North Carolina State University last year with majors in the mathematical sciences are $45,000, $50,000, and $40,000. (Note: do not use $ symbols or commas in your answers.) (a) Report the sample statistic that can be used to estimate the population mean starting salaries of all math science graduates at that university last year (whole number, no commas) (b) The margin of error for a 95% confidence interval for the true mean starting income is $12,421. Construct a 95% confidence interval Lower Limit Upper Limit = $ (c) Mark all statements below that are true. (whole number, no commas) (whole number, no commas) A sample statistic is more accurate than an interval estimate A sample statistic is preferred to an interval estimate because it gives an exact value. An interval estimate is preferred to a sample statistic because an interval estimate gives a range of plausible values. An interval estimate is preferred to a sample statistic because a sample statistic alone may be inaccurate, especially if the sample size is small.

Answer 1

a) Sample statistic = Sample mean = (45000 + 50000 + 40000)/3 = $ 45000

b) 95% confidence interval:

Lower limit = 45000 - 12421 = $ 32579

Upper limit = 45000 + 12421 = $ 57421

c) Option C and Option D are correct.