Answer:
The margin of error of the 90% confidence interval of a student's average typing speed is of 1.933 wpm.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used 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 = 20 - 1 = 19
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 19 degrees of freedom(y-axis) and a confidence level of 
. So we have T = 1.7291
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample. For this question, we have 
. So
The margin of error of the 90% confidence interval of a student's average typing speed is of 1.933 wpm.
Answer:
The margin of error is of 0.3012, and it means that we should be 99% confident that the population mean would be within 0.3012 of the sample mean.
Step-by-step explanation:
Margin of error
In which 
is the standard deviation and n is the size of the sample.
Standard deviation of 1.3
This means that 
She surveys 124 families
This means that 
Margin of error and meaning:
The margin of error is of 0.3012, and it means that we should be 99% confident that the population mean would be within 0.3012 of the sample mean.
Answer:
x = -7
Step-by-step explanation:
Given parameters:
Slope of the line = 
Coordinates = (5,x) and (2,-3)
Unknown:
X= ?
Solution:
To find slope, use the expression below;
Slope = 
y₂ = -3 y₁ = x
x₂ = 2 x₁ = 5
= 
3(-3-x) = 4(-3)
-9 -3x = 12
-3x = 21
x = -7
The fourth one best summarizes the passage
