Answer:
The 95% confidence interval for the average number of units that students in their college are enrolled in is between 11.7 and 12.5 units.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 45 - 1 = 44
95% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 44 degrees of freedom(y-axis) and a confidence level of 
. So we have T = 2
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 12.1 - 0.4 = 11.7 units
The upper end of the interval is the sample mean added to M. So it is 12.1 + 0.4 = 12.5 units
The 95% confidence interval for the average number of units that students in their college are enrolled in is between 11.7 and 12.5 units.
Answer:
56.55 inches
Step-by-step explanation:
Add 1 to both sides:
In cases like this, we have to remember that a root is always positive, so we can square both sides only assuming that
Under this assumption, we square both sides and we have
The solutions to this equation are
But since we can only accept solutions greater than -1, we discard 
and accept 
.
In fact, we have
and
which is the only solution.
Answer:
9*(6+7)
Step-by-step explanation:
First, we have to find the Greatest Common Factor (GCF), to do this we have to see all the factors of 54 and 63 and find the greatest factor that they have in common.
Factors of 54
1,2,3,6,9,18,27,54
Factors of 63
1,3,7,9,21,63
The GCF is 9 because is the greatest factor that is common to both numbers.
Now we have to divide 54/9 and 63/9
54/9 = 6
63/9 = 7
So now we can write the product of the GCF and another sum:
9*(6+7)
<em>We can prove this by solving both expressions:</em>
<em>54+63 = 9*(6+7)</em>
<em>117 = 9*13</em>
<em>117 = 117 </em>
<em>The results are equal so we prove it is right.</em>
