NCERT Class 11-Math's: Exemplar Chapter –15 Statistics Part 4
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Question 2:
Marks Obtained | |||||
No. of Student |
Answer:
Question 3:
Calculate the mean deviation about the mean of the set of first natural numbers when is an odd number.
Answer:
Question 4:
Calculate the mean deviation about the mean of the set of first natural numbers when is an even number.
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Question 5:
Find the standard deviation of the first n natural numbers.
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Question 6:
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 , mean seconds, standard deviation seconds.
Further, another set of observations , also in seconds, is now available and we have and . Calculate the standard derivation based on all observations.
Answer:
Question 7:
The mean and standard deviation of a set of observations are and , respectively while the mean and standard deviation of another set of observations are and , respectively. Show that the standard deviation of the combined set of observations is given by
Answer:
Question 8:
Two sets each of observations, have the same standard derivation. The first set has a mean and the second a mean . Determine the standard deviation of the set obtained by combining the given two sets.
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Question 9:
The frequency distribution:
1 |
where A is a positive integer, has a variance of . Determine the value of A.
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Question 10:
For the frequency distribution:
Find the standard distribution.
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Question 11:
There are students in a class. The following is the frequency distribution of the marks obtained by the students in a test:
Marks | ||||||
Frequency |
Where is a positive integer. Determine the mean and standard deviation of the marks.
Answer:
Question 12:
The mean life of a sample of bulbs was hours and the standard deviation was hours. A second sample of bulbs has a mean life of hours and standard deviation hours. Find the overall standard deviation.
Answer: