Critical values problem


I'm a complete newbie in the stats game, and I'm stuck on a problem in my book. It seems rather basic to me - so I hesitate to move on before understanding how to solve it. Would highly appreciate if someone could help me out with this by explaining the approach I should take. The problem is as follows:

For mean=75, standard dev=10 and N=25, find the critical values for (a) alpha=0.05, one-tailed, and (b) alpha=0.01, two-tailed.

As it does not explicitly say the distribution is normal, I assume that it would be insufficient to look up Z-scores related to the alpha levels? This assumption is strengthened by the fact that these scores do not match the answers to the problem. Also, if this was the solution I guess the information about mean, standard dev and N would be irrelevant?

Would love some help with getting unstuck so that I can move on in the world of stats!


Less is more. Stay pure. Stay poor.
Can you post the question exactly from source (may even a screenshot). And if it came from a textbook, cite page, problem, and reference. Many times posters accidently leave out information.