The mean and standard deviation for a b and 2 are 3 and 2 √ 3 respectively the value of ab would be
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Answered by
81
Answer:
ab = -5
Step-by-step explanation:
The mean and standard deviation for a b and 2 are 3 and 2 √ 3 respectively the value of ab would be
Mean = (a + b + 2)/3 = 3
=> a + b + 2 = 9
=> a + b = 7
Standard deviation = √∑(x - Mean)²/n
=> 2√3 = √∑(x - Mean)²/n
squaring both sides
=> 12 = ∑(x - Mean)²/n
n = 3
=> 12 = ∑(x - Mean)²/3
=> 36 = ∑(x - Mean)²
∑(x - Mean)² = (a-3)² + (b-3)² + (2-3)² = a² + 9 -6a + b² + 9 - 6b + 1
= a² + b² -6a -6b + 19
equating both
a² + b² -6a -6b + 19 = 36
using a² + b² = (a + b)² - 2ab
=> (a+b)² - 2ab - 6(a+b) + 19 = 36
putting value of a + b = 7
=> 7² - 2ab - 6(7) = 17
=> 49 - 2ab - 42 = 17
=> -2ab = 10
=> ab = -5
Answered by
40
Answer:
,
Step-by-step explanation:
for detailed step bye step answer see attachment ....
ab=11 ..is correct answer
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