Answer:
Step-by-step explanation:
The mean SAT score is
, we are going to call it \mu since it's the "true" mean
The standard deviation (we are going to call it
) is

Next they draw a random sample of n=70 students, and they got a mean score (denoted by
) of 
The test then boils down to the question if the score of 613 obtained by the students in the sample is statistically bigger that the "true" mean of 600.
- So the Null Hypothesis 
- The alternative would be then the opposite 
The test statistic for this type of test takes the form

and this test statistic follows a normal distribution. This last part is quite important because it will tell us where to look for the critical value. The problem ask for a 0.05 significance level. Looking at the normal distribution table, the critical value that leaves .05% in the upper tail is 1.645.
With this we can then replace the values in the test statistic and compare it to the critical value of 1.645.

<h3>since 2.266>1.645 we can reject the null hypothesis.</h3>
Answer:
The mean increases and the median changes to 4.
Step-by-step explanation:
To find the mean. You need to add all of the numbers together then divide by how many numbers there are. The median is found by the middle number.
Answer:
Length = 21
Width = 16
Step-by-step explanation:
We know that the formula for perimeter is:
P=2W+2L
And we also know that:
L=W+5
So then we put all that we know in the formula:
74=2W+2(W+5)
Now we expand the brackets and do some algebra:
74=4W+10 (-10)
64=4W (÷4)
16=W
Now that we know the width we can pop that into the length equation:
L=16+5
L=21
Answer: 4. (-1,-1) 3. (3,-2)
4)
Set the equations equal to each other.
4x+3=-x-2
Subtract 3 from both sides
4x=-x-5
Add x to both sides
5x=-5
Divide both sides by 5
x=-1
Next, replace x with -1 in either equation to find y.
-(-1)-2=y
-1=y
3)
Do the same thing for this one and set them equal to each other
-2x+4=-1/3x-1
Add 1 to both sides
-2x+5=-1/3x
Add 2x to both sides
5=5/3x
Divide both sides by 5/3
x=3
Next, replace x with 3 in either equation
-2(3)+4=y
-2=y