You should put a picture of the problem so I can help
Answer:
Mean = 0.4
Stand deviation = 0.08944
Step-by-step explanation:
1.
This question tells us that the mean of trapped moths is only 0.4
Therefore the mean = E(X) = 0.4
2.
The standard deviation of the sample mean is
= σ/√n
σ = 0.6
n = 45
When we put these values into the formula we will have:
0.6/√45
= 0.6/6.708
= 0.08944
So in conclusion, the mean is 0.4 and the standard deviation is 0.08944.
Thank you!
Answer:
n = 125
Step-by-step explanation:
<u>Step 1: Convert words into an expression</u>
Number n is 25 less than 120% of itself. What is the value of n?
25 less than 120% of itself can be represented as: <u>1.2n - 25</u>
n = 1.2n - 25
<u>Step 2: Add Subtract 1.2 from both sides</u>
n - 1.2n = 1.2n - 25 - 1.2n
-0.2n = -25
<u>Step 3: Divide both sides by -0.2</u>
-0.2n / -0.2 = -25 / -0.2
<em>n = 125</em>
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Answer: n = 125
In a normal distribution, the median is the same as the mean (25.3). The first quartile is the value of

such that

You have

For the standard normal distribution, the first quartile is about

, and by symmetry the third quartile would be

. In terms of the MCAT score distribution, these values are


The interquartile range (IQR) is just the difference between the two quartiles, so the IQR is about 8.8.
The central 80% of the scores have z-scores

such that

That leaves 10% on either side of this range, which means

You have

Converting to MCAT scores,


So the interval that contains the central 80% is

(give or take).
Spider-Man 120
Superman 40