Answer:
The critical value that should be used is T = 2.0796.
The 95% confidence interval for the mean repair cost for the dryers is between $91.912 and $105.648.
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 = 22 - 1 = 21
95% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 21 degrees of freedom(y-axis) and a confidence level of 
. So we have T = 2.0796, which is the critical value that should be used.
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 98.78 - 6.868 = $91.912
The upper end of the interval is the sample mean added to M. So it is 98.78 + 6.868 = $105.648
The 95% confidence interval for the mean repair cost for the dryers is between $91.912 and $105.648.
Answer:
<em>797.0ft²</em>
Step-by-step explanation:
<u>Find a related diagram attached</u>
Area of the gate = Area of the semicircle + Area of the Rectangle
Area of the semicircle = πr²/2
r is the radius
From the diagram, radius r = 20/2 = 10ft
Area of the semicircle = 3.14(10)²/2
Area of the semicircle = 3.14(100)/2
Area of the semicircle = 314/2
Area of the semicircle = 157ft²
Area of the rectangle = Length * Width
Area of the rectangle = 20*32
Area of the rectangle = 640ft²
Area of the gate = 157 + 640
Area of the gate = 797ft²
<em>Hence the area of the gate is 797.0ft²</em>
Answer:
66yx , 30x2y, hope its right :)
Step-by-step explanation:
Hello there.
Question: <span>A school principal wants to find out if his school needs more bike racks. a survey is taken of 30 students who ride their bikes to school. why might the sample be biased?
Answer: It might be biased as the survey was only taken of students who ride their bikes to school. It is most likely that they would agree to it. To make it fair they survey should have been taken of a variety of different students.
Hope This Helps You!
Good Luck Studying ^-^</span>
Answer:
a) 0.70
b) 0.30
c) 12/45 =4/15
d) 2/45
Step-by-step explanation:
a) Prob of drawing a marble red or white = No of red and white marbles/total marbles
= 7/10 = 0.70
b) Prob of drawing a marble neither red nor white = 1-7/10 = 0.30
c) Prob of drawing two marble one red and one white at the same time
= 
d) Prob of drawing two marble one blue and orange white at the same time
= 
