Scary Medical Statistics: Lost In Interpretation!

Data Sheet

70 patients took part in this study. Half of them had a snack of bread and jam, and the others a high glucose drink.

Their blood samples were taken at various intervals after their snack or drink (0, 30, 60 and 90 minutes).

Results for blood glucose levels are given in the tables shown here.

Blood glucose levels are expressed in millimoles per litre (mmol/l).

How can you analyse these results?

What would you expect the results to show?

How could these results be manipulated to give a different conclusion?

If you want, each table can be copied and pasted into a spreadsheet (such as Microsoft Excel).

Time (mins) 0 30 60 90
Patient Number
1 6.5 11.2 9.7 7.5
2 6.3 7.9 9.6 6.7
3 4.6 6.9 7.7 6.9
4 8.7 13.6 9.9 11.4
5 7.3 10.2 9.6 8.5
6 6.1 11.7 11.5 10.3
7 5.5 8.0 6.9 7.3
8 6.6 7.8 8.9 8.6
9 8.2 12.0 8.8 5.9
10 4.1 9.0 9.4 6.8
11 6.3 15.2 26.3 9.9
12 7.7 8.7 8.4 7.4
13 4.4 10.2 5.5 7.9
14 6.3 15.5 9.4 8.0
15 6.1 7.6 13.5 9.8
16 10.0 8.1 7.6 7.1
17 8.3 13.3 14.3 7.8
18 10.5 8.6 7.8 8.7
19 5.3 7.9 4.8 4.6
20 5.2 10.6 8.8 6.0
21 3.8 8.8 10.8 8.2
22 3.6 5.2 6.7 6.0
23 3.7 11.3 10.4 9.2
24 4.3 7.3 6.4 5.2
25 4.7 7.8 8.8 7.3
26 5.6 5.1 5.7 4.4
27 7.2 7.2 5.2 5.4
28 4.2 6.1 8.4 8.0
29 4.1 6.0 5.2 4.7
30 3.3 6.6 5.2 5.8
31 4.0 6.2 5.3 5.1
32 4.8 6.8 5.3 5.1
33 4.1 6.5 5.9 3.9
34 4.6 7.0 6.1 5.6
35 4.7 7.1 6.9 5.2

High glucose drink

Time (mins) 0 30 60 90
Patient Number
1 5.1 9.9 9.4 5.5
2 4.9 11.5 6.6 7.7
3 7.1 5.6 7.3 8.1
4 4.4 11.6 8.6 8.1
5 4.9 9.1 7.9 7.4
6 4.2 7.2 6.6 6.9
7 6.7 15.6 7.2 4.7
8 4.2 7.5 5.4 6.4
9 6.3 9.1 7.6 7.1
10 6.2 10.4 9.2 7.7
11 6.9 8.1 7.3 5.0
12 8.1 11.2 7.7 8.3
13 12.0 11.0 9.8 8.9
14 4.6 11.0 7.2 6.8
15 5.0 10.4 9.3 8.4
16 7.8 13.0 7.6 7.2
17 4.8 6.6 6.2 5.7
18 4.5 7.2 5.7 5.2
19 3.6 8.5 8.6 6.4
20 4.3 8.2 8.9 8.6
21 5.3 12.3 7.8 6.9
22 4.5 7.3 6.8 5.2
23 5.0 8.3 5.1 5.9
24 3.7 5.9 5.3 5.1
25 4.2 8.5 6.6 5.3
26 4.2 8.2 5.7 5.1
27 4.7 8.4 8.3 6.2
28 4.6 9.2 6.6 4.3
29 3.7 8.0 5.2 4.9
30 4.7 8.9 5.6 5.9
31 4.1 9.8 7.1 6.0
32 3.3 6.0 5.2 4.8
33 3.9 7.0 10.4 8.8
34 4.4 8.6 5.7 5.2
35 4.1 7.2 5.7 4.7