Biological Data Analysis: Homework 7

Due Tuesday, Oct. 21



You must type this and all other homework assignments. Do not e-mail the assignment to me; turn it in early (at 322 Wolf) for a foreseeable absence, or turn it in late after an unexpected absence from class.

1. Two technicians, "Brad" and "Janet" (these are real data, but I've changed their names), have measured the uptake of a fluorescently labelled protein in rat kidneys. They want to know whether their techniques for anesthetizing the rats, cutting them open, and injecting the fluorescently labelled protein are the same. They also want to know whether it's worthwhile to use multiple rats, and whether it's worthwhile to make multiple measurements from each rat. Brad operates on three rats, then after 60 minutes, measures the protein in 10 samples from each rat. Janet does the same on three rats of her own. The data are below question 2. Analyze the data using a nested anova. Report the F-statistics and P-values for each null hypothesis. You must use my spreadsheet, and you must also analyze the data using SAS. If you get the same P-values in SAS as you did with the spreadsheet (note that SAS may round to a smaller number of decimals), you only need to print the SAS output (from the .lst file). If you get a different result from my spreadsheet and from SAS, you must also print the .log file and your SAS program (your .sas file), so I can try to figure out what you did wrong.

2. interpret the results of question 6--what would you recommend to Brad and Janet?


Tech  Rat  Protein

Janet   1   1.119
Janet   1   1.2996
Janet   1   1.5407
Janet   1   1.5084
Janet   1   1.6181
Janet   1   1.5962
Janet   1   1.2617
Janet   1   1.2288
Janet   1   1.3471
Janet   1   1.0206
Janet   2   1.045
Janet   2   1.1418
Janet   2   1.2569
Janet   2   0.6191
Janet   2   1.4823
Janet   2   0.8991
Janet   2   0.8365
Janet   2   1.2898
Janet   2   1.1821
Janet   2   0.9177
Janet   3   0.9873
Janet   3   0.9873
Janet   3   0.8714
Janet   3   0.9452
Janet   3   1.1186
Janet   3   1.2909
Janet   3   1.1502
Janet   3   1.1635
Janet   3   1.151
Janet   3   0.9367
Brad    5   1.3883
Brad    5   1.104
Brad    5   1.1581
Brad    5   1.319
Brad    5   1.1803
Brad    5   0.8738
Brad    5   1.387
Brad    5   1.301
Brad    5   1.3925
Brad    5   1.0832
Brad    6   1.3952
Brad    6   0.9714
Brad    6   1.3972
Brad    6   1.5369
Brad    6   1.3727
Brad    6   1.2909
Brad    6   1.1874
Brad    6   1.1374
Brad    6   1.0647
Brad    6   0.9486
Brad    7   1.2574
Brad    7   1.0295
Brad    7   1.1941
Brad    7   1.0759
Brad    7   1.3249
Brad    7   0.9494
Brad    7   1.1041
Brad    7   1.1575
Brad    7   1.294
Brad    7   1.4543


3. Brad and Janet are also developing a new technique to measure the uptake of proteins by liver cells. They inject a fluorescently labelled protein into one rat, wait one minute, then they each take 12 samples of liver cells from the rat. Using confocal microscopy, they measure the amount of fluorescent protein taken up by the cells in each sample. They take more samples after 60 minutes. You want to know whether the two technicians are getting similar results, or whether one technician gets higher or lower measurements than the other. You also want to know whether there's a difference between the readings at one and 60 minutes. Analyze these data using a two-way anova (you'll have to use SAS for this). Show your SAS program and your SAS output; you only need to print the SAS log file if you think you have a problem. Give your interpretation of the results--what would you recommend to Brad and Janet about how they measure protein uptake in the future?


Tech     Time    Protein

Brad      1min    0.9490
Brad      1min    1.1265
Brad      1min    1.0468
Brad      1min    0.9341
Brad      1min    1.2349
Brad      1min    1.2827
Brad      1min    0.9586
Brad      1min    1.1753
Brad      1min    0.9724
Brad      1min    1.1382
Brad      1min    0.9511
Brad      1min    1.2837
Brad     60min    1.1248
Brad     60min    1.3274
Brad     60min    1.1669
Brad     60min    1.3987
Brad     60min    1.3338
Brad     60min    1.4191
Brad     60min    1.5732
Brad     60min    1.6369
Brad     60min    1.2153
Brad     60min    1.7057
Brad     60min    1.4904
Brad     60min    1.2777
Janet     1min    1.0524
Janet     1min    1.1819
Janet     1min    1.2548
Janet     1min    1.0275
Janet     1min    1.3676
Janet     1min    1.2186
Janet     1min    1.4215
Janet     1min    1.3880
Janet     1min    1.1413
Janet     1min    1.0530
Janet     1min    0.9133
Janet     1min    0.9174
Janet    60min    1.2257
Janet    60min    1.2559
Janet    60min    1.1268
Janet    60min    1.6080
Janet    60min    1.7720
Janet    60min    1.5759
Janet    60min    1.5887
Janet    60min    1.3341
Janet    60min    1.2031
Janet    60min    1.4293
Janet    60min    1.2388
Janet    60min    1.5600


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This page was last revised October 16, 2014. Its URL is http://udel.edu/~mcdonald/stathw7.html