The parameter of interest in this scenario is the proportion of all 1,000 students within the school who have "strict" parents or guardians.
<h3>How to calculate a test statistic?</h3>
In Mathematics, the test statistics of a given sample is calculated by using this formula:

<u>Where:</u>
- is the standard deviation.
In conclusion, a possible test statistic which can be used to estimate this parameter is the proportion of all students who have "strict" parents or guardians, based on the collected sample.
Read more on test statistic here: brainly.com/question/4621112
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If they’re all weighted equally, then your average grade will be 79.9%
Answer: yes , it is possible
Step-by-step explanation:
Let the first number be x and the second number be y .Then , the sum of the two numbers will be x + y , and their difference will be x - y.
Combining the two , we have :
x + y = 1 ............................... equation 1
x - y = 8 ................................. equation 2
solving the system of linear equation by substitution method. From equation 1 , make x the subject of the formula ,
x = 1 - y ...................... equation 3
Substitute equation 3 into equation 2 ,
1 - y - y = 8
1 - 2y = 8
add 2y to both sides
1 = 8 + 2y
subtract 8 from both sides
1 - 8 = 2y
- 7 = 2y
divide through by 2
y = 
y = - 3.5
substitute y = -3.5 into equation 3 to find the value of x , we have
x = 1 - y
x = 1 - ( - 3.5 )
x = 1 + 3.5
x = 4.5
Let us check :
x + y will be
4.5 + (-3.5) = 1
Also ,
x - y will be
4.5 - (-3.5)
⇒ 4.5 + 3.5 = 8
7 - 9w = - 29
Subtract 7 from both sides
- 9w = - 36
Divide by - 9 on both sides
w = 4