Math 210
Laboratory 13
Inference for the Mean of a Population


  1. For the first part of this lab you will estimate the mean age of  pennies.  In 2001, a number pennies were collected and the dates were recorded.  These dates can be found here.
    1. Graph the penny data in a histogram and describe its shape.  (Graph > Histogram > Simple)
    2. Find the sample mean and standard deviation.  (Stat > Basic Statistics > Display Descriptive Statistics)
    3. Find a 95% confidence interval for the population mean for the data set.  (Stat > Basic Statistics > 1-Sample t)
    4. Given the shape of the distribution and the size of the sample, explain if it is appropriate to use the t-procedures on the data.  Explain this so I know the you understand how size and shape affect the use of the t-procedures.
    5. What is the standard error of the mean for this data set?

  1. For the next part of the lab, we will look at weights of coffee.  Ten samples of 0.5 pound bags of hazelnut coffee from a local coffee house were weighed.  The results, in pounds, are as follows.
0.48, 0.51, 0.47, 0.49, 0.49, 0.50, 0.52, 0.48, 0.49, 0.51
    1. Find the sample mean and standard deviation for the coffee data.
    2. Using the coffee data, determine if the population mean of all hazelnut coffee has a mean weight less than the label weight of 0.5 pounds.  Report the hypotheses, P-value, and conclusion (write the conclusion out in words using no symbols.)  (Stat > Basic Statistics > 1-Sample t.  Put in 0.5 for the Test Mean, click on options and choose the appropriate alternative hypothesis.)

  1. For the final part of the lab, we will look at test grades of 46 statistics students for test 2 and test 3.  These scores can be found here.
    1. Find the means for both tests.
    2. Subtract the scores for test 2 from the scores for test 3.  (Calc > Calculator.)  This will give the increase in score from test 2 to test 3.  Use this difference to complete a match pair test to see if scores for test 3, in general, are higher than those for test 2.  Report the hypotheses, P-value, and conclusion (write the conclusion out in words using no symbols.)