Please select a subject first
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The connective in the statement “Earth revolves round the Sun and Moon is a satellite of earth” is ______.
Concept: undefined >> undefined
The negation of the statement “A circle is an ellipse” is ______.
Concept: undefined >> undefined
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The negation of the statement “7 is greater than 8” is ______.
Concept: undefined >> undefined
The negation of the statement “72 is divisible by 2 and 3” is ______.
Concept: undefined >> undefined
The negation of the statement “Plants take in CO2 and give out O2 ” is ______.
Concept: undefined >> undefined
The negation of the statement “Rajesh or Rajni lived in Bangalore” is ______.
Concept: undefined >> undefined
The negation of the statement “101 is not a multiple of 3” is ______.
Concept: undefined >> undefined
Which of the following is the conditional p → q?
Concept: undefined >> undefined
The negation of the statement “The product of 3 and 4 is 9” is ______.
Concept: undefined >> undefined
Which of the following is not a negation of “A natural number is greater than zero”?
Concept: undefined >> undefined
Which of the following statement is a conjunction?
Concept: undefined >> undefined
State whether the following sentences are statements are not.
(i) The angles opposite to equal sides of a triangle are equal.
(ii) The moon is a satellite of earth.
(iii) May God bless you!
(iv) Asia is a continent.
(v) How are you?
Concept: undefined >> undefined
Show that the two formulae for the standard deviation of ungrouped data.
`sigma = sqrt((x_i - barx)^2/n)` and `sigma`' = `sqrt((x^2_i)/n - barx^2)` are equivalent.
Concept: undefined >> undefined
Life of bulbs produced by two factories A and B are given below:
| Length of life (in hours) |
Factory A (Number of bulbs) |
Factory B (Number of bulbs) |
| 550 – 650 | 10 | 8 |
| 650 – 750 | 22 | 60 |
| 750 – 850 | 52 | 24 |
| 850 – 950 | 20 | 16 |
| 950 – 1050 | 16 | 12 |
| 120 | 120 |
The bulbs of which factory are more consistent from the point of view of length of life?
Concept: undefined >> undefined
A set of n values x1, x2, ..., xn has standard deviation 6. The standard deviation of n values x1 + k, x2 + k, ..., xn + k will be ______.
Concept: undefined >> undefined
Find the standard deviation of the first n natural numbers.
Concept: undefined >> undefined
The mean and standard deviation of some data for the time taken to complete a test are calculated with the following results:
Number of observations = 25, mean = 18.2 seconds, standard deviation = 3.25 seconds. Further, another set of 15 observations x1, x2, ..., x15, also in seconds, is now available and we have `sum_(i = 1)^15 x_i` = 279 and `sum_(i = 1)^15 x^2` = 5524. Calculate the standard derivation based on all 40 observations.
Concept: undefined >> undefined
The mean and standard deviation of a set of n1 observations are `barx_1` and s1, respectively while the mean and standard deviation of another set of n2 observations are `barx_2` and s2, respectively. Show that the standard deviation of the combined set of (n1 + n2) observations is given by
S.D. = `sqrt((n_1(s_1)^2 + n_2(s_2)^2)/(n_1 + n_2) + (n_1n_2 (barx_1 - barx_2)^2)/(n_1 + n_2)^2)`
Concept: undefined >> undefined
Two sets each of 20 observations, have the same standard derivation 5. The first set has a mean 17 and the second a mean 22. Determine the standard deviation of the set obtained by combining the given two sets.
Concept: undefined >> undefined
The mean life of a sample of 60 bulbs was 650 hours and the standard deviation was 8 hours. A second sample of 80 bulbs has a mean life of 660 hours and standard deviation 7 hours. Find the overall standard deviation.
Concept: undefined >> undefined
