Answer: the sample size should be 39
Step-by-step explanation:
The sample mean is the point estimate for the population mean. Confidence interval is written as
Sample mean ± margin of error
Margin of error = z × σ/√n
Where
σ = population standard Deviation
n = number of samples
z represents the z score corresponding to the confidence level
From the information given,
σ = 4 minutes
Margin of error = 75 seconds. Converting to minutes, it becomes 75/60 = 1.25 minutes
To determine the z score, we subtract the confidence level from 100% to get α
α = 1 - 0.95 = 0.05
α/2 = 0.05/2 = 0.025
This is the area in each tail. Since we want the area in the middle, it becomes
1 - 0.025 = 0.975
The z score corresponding to the area on the z table is 1.96. Thus, confidence level of 95% is 1.96
Therefore,
1.25 = 1.96 × 4/√n
1.25/1.96 = 4/√n
0.6378 = 4/√n
√n = 4/0.6378 = 6.27
n = 6.27² = 39
Answer:
x = 128
Step-by-step explanation:
Adjacent angles - Angles right next to each other. They share a common vertex
Vertical angles - angles that are vertically aligned with each other.
The angle that has a measure of 128 degrees and x are vertical angles
If you didn't know vertical angles are congruent so because one angle equals 128 degrees the other equals 128 degrees
x = 128
Answer:
3
Step-by-step explanation:
One way you could do this is by dividing 94 by 3 and then 95 by 4. This gives you the KPH (Kilometers per hour) of both trains. The first speed you mentioned, we will call that speed 'A.' The second one will be speed 'B.' Speed A's KPH is 23.75 MPH. Speed B's KPH is 31.333. We can change these into fractions (23 3/4 and 31 1/3.) These fractions could then be set into like terms. (This gives us 285/12 and 376/12) We then add these together. This gives us 661/12. The next thing to do is to convert this back to a decimal form, which gives us 55.0833.... Divide this number by two, and that is your answer. The average speed of the train is 29.04 KPH (This number is rounded to the nearest hundreth- be sure to make a note of that on your answer sheet)
Answer:
Step-by-step explanation:
From the question we are told that:
Fan oscillates 
Distance 
Since
Generally the equation for the area A is mathematically given by
Where
Therefore the area A is given as
