There were 270*100/30 = 900 total finishers. 90% completed the marathon, so 900*100/90 = 1000 began the marathon. 1,000 runners total.
Question:
For a population with a mean of μ=45 and a standard deviation of σ=10. What is the corresponding z score if it has a score of X = 44?
Answer:

Explanation:
Given



Required
Calculate the z score
This is calculated as:

So:



The frequency of the sinusoidal graph is 3 Hz.
<h3>What is frequency of sinusoidal graph?</h3>
The frequency of a sinusoidal graph is the number of complete waves for every 2π units.
The frequency of the sinusoidal graph is determined by counting the number of complete waves from
to
units.
From a sketch of the graph;


Thus, the frequency of the sinusoidal graph is 3 Hz.
Learn more about frequency of sinusoidal graphs here: brainly.com/question/12075992