I did the math and I think it should be 67.5
491,111 is greater than 409,867
Answer:
flip it around 9/13 reciprocal would be 13/9
The correct option is 20.
The score found for the sample is 20.
<h3>What is Standard error?</h3>
A standard error is a statistic that is applied to test the distribution of data. This metric is comparable to standard deviation. We can calculate the standard error if we know the sample size & standard deviation. It assesses the mean's precision.
Now, according to the question;
Sample mean; 
Sample variance; 
Thus, 
Standard error SE = 1
The amount of scores with in sample must be determined here.
The standard error formula is as follows:

We might rearrange the formula as follows:

Substituting the values;

The sample's number of scores n = 19.98 = 20 (round up)
Therefore, the scores are in the sample is 20.
To know more about the Standard error, here
brainly.com/question/14467769
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Answer:
225
Step-by-step explanation:
Mary = 3x (3 times Carey)
Carey = x
Barry = x/2 (Because Carey read twice as many as Barry, it means he read half the amount Carey did)
3x + x + x/2 = 405
4x + x/2 = 405
8x/2 + x/2 (treat these as fractions) = 405
9x/2 = 405
9x = 810 (cross multiply)
x = 90
Mary = 3(90) 270
Carey = 90
Barry = 90/2 45
Mary - Barry
270 - 45 = 225
Hope this helps! :)