ab.news(a)laposte.net @ INTERNET skrev 2007-09-18 00:13:18 :
Otherwise, there are two small bugs in the "Tools" menu.
1. On the "Test calculator" window, when you check the "Assume std
dev ..." option and click Ok a pop-up appears saying "Bad PNG
header: Got bytes e0 22 0" and it doesn't produce the distribution graph.
I got the same kind of error for the test statistic calculator for test of
2 proportions, but the pop-up says "Bad PNG header: Got bytes fc e0 22 0"
instead.
Also, no graph is produced.
BTW, if one by mistake inputs a number instead of a proportion, one gets
the following weird output:
Null hypothesis: the population proportions are equal
Sample 1:
n = 450, proportion = 10
Sample 2:
n = 520, proportion = 12
Test statistic: z = (10 - 12) / -1.#IND = -1.#IND
Two-tailed p-value = 1.#QO
(one-tailed = 1.#QO)
I guess -1.#IND and 1.#QO are supposed to mean NA.
This is the Windows snapshot of version 1.6.6pre1 build date 09/17/2007.
Andreas