Final answer:
To calculate p(-1.91 < z < -0.25) in a standard normal distribution, find the areas to the left for z-scores -1.91 and -0.25 using a z-table, calculator, or software, and subtract the smaller area from the larger to get the difference.
Step-by-step explanation:
To find the probability p(-1.91 < z < -0.25) for a standard normal distribution, we look at the area under the standard normal curve between the z-scores of -1.91 and -0.25. We can use a z-table, calculator, or statistical software to find the corresponding probabilities for these z-scores.
First, we find the area to the left of z = -1.91, which is the cumulative probability up to that z-score. Next, we find the area to the left of z = -0.25. The desired probability is the difference between these two areas, because p(-1.91 < z < -0.25) is the area under the curve between these two z-scores. If we let A1 be the area to the left of z = -1.91 and A2 be the area to the left of z = -0.25, then the probability we are looking for is A2 - A1.
To calculate this using a z-table, look up the z-score -1.91, which gives us A1, and look up the z-score -0.25, which gives us A2. The difference will give you the answer to p(-1.91 < z < -0.25).