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.
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*the figure is shown in the attachment
Answer/Step-by-step explanation:
Since <XYZ and <YZX are said to be congruent, therefore, the side opposite to each of the angle are also equal. Therefore, ∆XYZ is an isosceles ∆.
Find the value of n by creating an equation to solve for n:
XY = (9n + 12) ft
XZ = (15n - 6) ft
XY = XZ (2 equal lengths of isosceles ∆)
9n + 12 = 15n - 6 (substitution)
Combine like terms
9n - 15n = - 12 - 6
-6n = -18
Divide both sides by -6
-6n/-6 = -18/-6
n = 3
Find the length of leg XY by substituting n = 3 into XY = (9n + 12) ft.
XY = (9(3) + 12) ft
XY = (27 + 12) ft
XY = 39 ft
Find the length of leg XZ by substituting n = 3 into XZ = (15n - 6) ft.
XZ = (15(3) - 6) ft
XZ = (45 - 6) ft
XZ = 39 ft
Answer:
Distance from point AA to point BB = 189.3 feet
Step-by-step explanation:
Let the distance from point AA to the base of the lighthouse be represented by x, and the distance from point BB to the base of the lighthouse be represented by y. So that;
distance from point AA to point BB = x - y
To determine the value of x, applying the required trigonometric function;
Tan θ = 
Tan 13 = 
x = 
= 441.81 feet
x = 441.8 feet
To determine the value of y;
Tan 22 = 
y = 
= 252.46
y = 252.5 feet
Thus,
distance from point AA to point BB = 441.8 - 252.5
= 189.3 feet
Answer:
add here be back charger
Step-by-step explanation:
