Suppose that people's heights (in centimeters) are normally distributed, with a mean of 170 and a standard deviation of 5. We find the heights of 60 people.How many would you expect to be between 170 and 175 cm tall? How many would you expect to be taller than 177 cm?

Question

anonymous · Answer

I'm hoping to get help on the formula here I don't understand it very well

kropot72 · Answer

The first part of your question can be solved by reference to the empirical rule:
'Approximately 68% of the data points lie within the range plus and minus one standard deviation of the population mean.'
In this question only plus one standard deviation is stated, therefore 34% of the data points are included.
What is 34% of 60?

anonymous · Answer

20.4

kropot72 · Answer

Good! So rounding the result we would expect to find approximately 20 people with heights in the range 170 to 175 cm.
For the second part of the question, do you know the formula for finding the z-score?