CSC 239: Personal Computing for Science

Fourth Assignment (Due 11:30pm Monday October 24, 2005)

Assignment

Problem 1

In a standard dissolution test for tablets of a particular drug product, the manufacturer must obtain the dissolution rate for a batch of tablets prior to release of the batch. Suppose that the dissolution test consists of assays for 24 randomly selected individual 25-mg tablets. For each test, the tablet is suspended in an acid bath and then assayed after 30 minutes. The result of the 24 assays are given in the file assay.txt.

Is there significant evidence that the batch of pills has a mean dissolution rate less than 20 mg (80% of the labeled amount in the tablets)? Use alpha=0.01.
  1. Use the work template created in class and this week's lab to compute the result of this significance test.
  2. Specify the null hypothesis and the alternative hypothesis of the test.
  3. Compute only the appropriate p-value.
  4. Use an appropriate IF statement to display the results of the test.
  5. Explain in non-technical words what the result of the test means.
Do all work for Problem 1 on a sheet named TabletData.

Problem 2

A geochemical and oceanographic survey of the inshore waters of Mombassa, Kenya was undertaken during the period from September 1995 to January 1996. In the survey, suspended particulate matter and sediment were collected in 37 stations and the lead concentration was measured. The researchers were interested in determining whether the average lead concentration was greater than 30 mg/kg dry weight. Data are given in the file lead.txt.

Is there sufficient evidence in the data that the mean lead concentration exceeds 30 mg/kg dry weight? Use alpha=0.01.
  1. Specify the null hypothesis and the alternative hypothesis of the test.
  2. Compute only the appropriate p-value.
  3. Use an appropriate IF statement to display the results of the test.
  4. Explain in non-technical words what the result of the test means.
Do all work for Problem 2 on a sheet named LeadData.

Additional challenge

For each problem above, calculate a p-value using the normal distribution instead of the t-distribution. To do this, you will need to use the NORMSDIST function in excel, there the z-value is the t-statistic that you calculated in the work table. Use the same basic structure as in the work table but use NORMSDIST instead of TDIST. Also, since the NORMSDIST function can handle negative values, you won't need to use the ABS function.

Deliverables

Submit your excel workbook using Course On-Line. Make sure that text answers are included in your workbook.