Final answer:
To find the proportion of observations where z is greater than 2.85, you subtract the area to the left of z=2.85 from 1 using a z-table, yielding the area to the right which is the sought proportion. For P(x > 65), convert 65 to a z-score using the mean and standard deviation before using the z-table.
Step-by-step explanation:
To find the proportion of observations for which z > 2.85, you would use a z-table or statistical software. The z-table provides the area under the standard normal curve to the left of a given z-score. However, the question asks for the area to the right, which represents the proportion we are interested in. If the z-table shows that the area to the left of z=2.85 is 0.9977, for example, subtracting this area from 1 will give the area to the right: 1 - 0.9977 = 0.0023. This is the proportion of observations for which z > 2.85. Additionally, if a problem asks to find P(x > 65), one would typically need the mean and standard deviation of the data set in question to convert 65 to a z-score first.