Answer:
157
Step-by-step explanation:
formula- 2 x 3.14 x 5 squared
6.28 x 5 squared
6.28 x 25
157
Answer:
There is a 34.13% probability that the actual return will be between the mean and one standard deviation above the mean.
Step-by-step explanation:
This is problem is solving using the Z-score table.
The Z-score of a measure measures how many standard deviations above/below the mean is a measure. Each Z-score has a pvalue, that represents the percentile of a measure.
What is the probability that the actual return will be between the mean and one standard deviation above the mean?
One measure above the mean is 
The mean is 
This means that this probability is the pvalue of
subtracted by the pvalue of
.
has a pvalue of 0.8413.
has a pvalue of 0.50.
This means that there is a 0.8413-0.50 = 0.3413 = 34.13% probability that the actual return will be between the mean and one standard deviation above the mean.
If he hits the target 95% of the time, then you could say that he has a probability of 0.95, or 95% of hitting the target. Let p = the probability of hitting the target or p = 0.95. So you are interested that he misses the target at least once - this could be thought of as not getting a perfect score. So to get a perfect score, it is 0.95 for each target -- 0.95^15 for 15 targets is 0.464. Thus to miss at least one target he needs to NOT have a perfect score -- 1 - 0.464 = 0.536, or 53.6% of happening. Enjoy