Answer:
D. 274
Step-by-step explanation:
A normal distribution of the scores is assumed. In the figure attached, the standard normal distribution table is shown.
If only top 5% of athletes are part of the team, then we need to find the value of the table which has a probability of 95%, that value is between 1.64 and 1.65, so we interpolate it as 1.645. The table was made for a variable with mean = 0 and standard deviation (sd) equal to 1, therefore to refer the result to our variable we compute:
1.645 = (x - mean)/sd
x = 1.645*sd + mean
x = 1.645*15 + 250 ≈ 274
So, 95% of the scores are below 274, then 274 is the minimum qualifying score
