The means and mean absolute deviations of Sidney’s and Phil’s grades are shown in the table below. Means and Mean Absolute Devia
2 answers:
Based on the given table, the mean grade of Sidney is 82, and the mean grade of Phil is 78. Moreover, the mean absolute deviation of Sidney is 3.28, and the mean absolute deviation of Phil is 3.96.
To find the difference between the two means, we just need to subtract the means of their grades. That is 82-78 or 4.
Therefore, the ratio <span>of the difference of the two means to Sidney’s mean absolute deviation is </span>
or 
or 1.2195.<span>
</span>
To find the difference between the two means, we just need to subtract the means of their grades. That is 82-78 or 4.
Therefore, the ratio <span>of the difference of the two means to Sidney’s mean absolute deviation is </span>
</span>
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The solution is n = 5 and r = 4
Step-by-step explanation:
Given,
nCr : (n+1)Cr : (n+2)Cr = 1:3:7
To find the value of n and r.
Formula
nCr = [ n! means = n.(n-1).(n-2)....3.2.1]
Now,
nCr : (n+1)Cr = 1:3 and (n+1)Cr : (n+2)Cr = 3:7
or, :
= 1:3 or,
:
=
or, ×
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or,
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or, =
or,
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or, 3(n+1-r) = n+1 or, 7(n+2-r) = 3(n+2)
or, 3n+3-3r = n+1 or, 7n+14-7r = 3n+6
or, 2n-3r = -2 or, 4n-7r = -8
Now, by solving
2n-3r = -2 -----(1)
4n-7r = -8 -----(2) we will get n and r
Multiplying (1) by and then subtract with (2) we get,
2(2n-3r) - (4n-7r) = -4-(-8)
or, 4n-6r-4n+7r = 4
or, r = 4
From (1) we get,
2n = -2+3(4)
or, 2n = 10
or, n = 5
Hence,
n = 5 and r = 4