Which one expression
1 answer:
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Answer:
The margin of error of u is of 3.8.
The 99% confidence interval for the population mean u is between 27.4 minutes and 35 minutes.
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 = 28 - 1 = 27
99% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 27 degrees of freedom(y-axis) and a confidence level of . So we have T = 2.7707
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample.
The margin of error of u is of 3.8.
The lower end of the interval is the sample mean subtracted by M. So it is 31.2 - 3.8 = 27.4 minutes
The upper end of the interval is the sample mean added to M. So it is 31.2 + 3.8 = 35 minutes
The 99% confidence interval for the population mean u is between 27.4 minutes and 35 minutes.
Answer:
The speed in of the plane is 115.47 m/sec
Step-by-step explanation:
Given:
Height at which the plane is flying = 6000 m
Angle of elevation at the radar base = 30 Degrees
Angle of elevation at the radar base after one minute = 60 Degrees
To Find:
The Speed of the plane in meter per second = ?
Solution:
Let us use the tangent of the angle to find the distance (d) to a point directly below plane:
<u>when the angle is 30 degrees</u>
d1 = 10392.3 meters
<u>when the angle is 60 degrees</u>
d2 = 3464.1 meters
<u>distance travelled by aircraft in 1 min is </u>
=>d1 - d2
=>0392.3 - 3464.1
= 6928.2 m/min
<u>Now converting to m/sec</u>
=>
=>115.47 m/sec