Can be used to compare changes from one period to another.
1 answer:
Answer:
c) Percentages
Step-by-step explanation:
Percentages can be used to compare changes from one period to another.
In calculating a percentage change, either a percentage increase or percentage decrease, we must have both the new and old measurement of the specific quantity.
For example, let's find percentage increase of the number of students that joined a book club using the parameters below;
Original number of students = 32
New number of students = 36
We will calculate the increase using;
Substituting the values, we have;
Increase = 36 - 32 = 4
Percentage increase = 12.5%
Therefore, the number of students in the school club increased by 12.5%.
You might be interested in
Answer:
a) To determine the minimum sample size we need to use the formula shown in the picture 1.
E is the margin of error, which is the distance from the limits to the middle (the mean) of the confidence interval. This means that we have to divide the range of the interval by 2 to find this distance.
E = 0.5/2 = 0.25
Now we apply the formula
n = (1.645*0.80/0.25)^2 = 27.7 = 28
The minimum sample size would be 28.
b) To answer the question we are going to make a 90% confidence interval. The formula is:
(μ - E, μ + E)
μ is the mean which is 127. The formula for E is shown in the picture.
E = 0.80*1.645/√8 = 0.47
(126.5, 127.5)
This means that the true mean is going to be contained in this interval 90% of the time. This is why it doesn't seem possible that the population mean is exactly 128.
