Answer:
B and C
Step-by-step explanation:
B is correct because 5² is 25, which is less than 64
C is correct because (-3)² is 9, which is less than 64
percent of the observations lie within plus and minus 2.5 standard deviations of the mean is 84%
according to Chebyshev's theorem k=2.5
Chebyshev theorem:
The minimum percentage of observations that are within a given range of standard deviations from the mean is calculated using Chebyshev's Theorem. Numerous other probability distributions can be applied with this theorem. Chebyshev's Inequality is another name for Chebyshev's Theorem.
This indicates that 1 - of the distribution will be close to the mean, or within k standard deviations.
Therefore, 1 -
⇒ 1-
⇒1-
⇒
⇒0.84
percent of the observations lie within plus and minus 2.5 standard deviations of the mean is 84%
Learn more about standard deviations here:
brainly.com/question/16555520
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Answer:
-3
Step-by-step explanation:
Let n be the number
product of seven and a number
7n
is negative 21
7n = -21
Divide each side by 7
7n/7 = -21/7
n = -3
The number is -3
Hi there!
~
cosec 20 -cot 40= 1/sin 20 - cos 40/sin 40
= (sin 40 -cos 40 sin20)/(sin 40 sin 20)
= 1/sin 40 ( 2 cos 20 - cos 40)
=1/sin20 ( 2 cos(60-40)-cos 40)
=1/sin40( 2 cos 60 cos 40 - 2 sin 60 -sin 40-cos 40)
Put the value of cos 60
= 1/sin 40 ( 2 sin 60 sin 40)
=root(3)
Hope this helped you!