Why is it that when we find the sample standard deviation, we ...

[melina_rosy]

Why is it that when we find the sample standard deviation, we divide by n-1 but when we find the population standard deviation we divide by n?
 
  What will be an ideal response?

Question 2

An emergency room in a hospital wants to determine the sample size needed for estimating their mean number of visits per day. If they want a 99 percent confidence level the correct critical value to use is 2.33.
 
  Indicate whether the statement is true or false

[Jsherida]

Answer to Question 1

The technical answer to this question is beyond the scope of the text. However, we can think of it this way. If our objective in computing the sample standard deviation is to estimate the population standard deviation, we would want an estimate that would be correct on the average. That means that if we took repeated random samples from the population and for each sample we computed the standard deviation, we would want the average of the sample standard deviations to equal the population standard deviation. If our formula for the sample standard deviation uses n-1, this occurs.

Answer to Question 2

FALSE

[melina_rosy]

Thanks for the timely response, appreciate it

[diana chang]

TYSM