Answer:
50%
Step-by-step explanation:
First, draw a normal distribution plot to use for the analysis of the data. Starting at the mean in the centre. Add one standard deviation for each interval to the right, and subtract one standard deviation for each interval to the right. See attached image. According to the empirical rule, 68% of data lies within one standard deviation of the mean, 95 % of the data is within two st. dev. and 99.7% of the data is within 3 st. dev. of the mean.
From the graph it can be deducted that half of the data will lie below 50, which makes it 50%.
An easier way of determining the answer is to use the definition of a mean. A mean is the number that,when all the data is placed in ascending order, lies right in the middle of all the data.
