The standard error of the difference of sample means is 0.444
From the complete question, we have the following parameters
<u>Canadians</u>
- Sample size = 50
- Mean = 4.6
- Standard deviation = 2.9
<u>Americans</u>
- Sample size = 60
- Mean = 5.2
- Standard deviation = 1.3
The standard error of a sample is the quotient of the standard deviation and the square root of the sample size.
This is represented as:

The standard error of the Canadian sample is:

So, we have:

The standard error of the American sample is:

So, we have:

The standard error of the difference of sample means is then calculated as:

This gives


Take square roots

Hence, the standard error of the difference of sample means is 0.444
Read more about standard errors at:
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Answer:
first what is the question
The value of
is -3. 
<h2>Procedure - Differentiability</h2><h3 /><h3>Chain rule and derivatives</h3><h3 />
We derive an expression for
by means of chain rule and differentiation rule for a product of functions:
(1)
If we know that
,
,<em> </em>
,<em> </em>
and
, then we have the following expression:




The value of
is -3. 
To learn more on differentiability, we kindly invite to check this verified question: brainly.com/question/24062595
<h3>Remark</h3>
The statement is incomplete and full of mistakes. Complete and corrected form is presented below:
<em>The point (-2, 4) lies on the curve in the xy-plane given by the equation </em>
<em>, where </em>
<em> is a differentiable function of </em>
<em> and </em>
<em> is a differentiable function of </em>
<em>. Selected values of </em>
<em>, </em>
<em>, </em>
<em> and </em>
<em> are given below: </em>
<em>, </em>
<em>, </em>
<em>, </em>
<em>. </em>
<em />
<em>What is the value of </em>
<em> at the point </em>
<em>?</em>
Answer:
This drug helps people lose more weight than diet and exercise alone. The reason for this statement is that with diet and exercise alone, 23% lost weight whereas with diet, exercise and the drug, 48% lost weight so the conclusion is that the drug enhanced weight loss.