NDA 2017 Paper 1 | Statistics Question 26 | Mathematics

The mean of a group of 100 observations was found to be 20. Later, it was found that four observations were incorrect, which were recorded as 21, 21, 18 and 20. What is the mean if the incorrect observation are omitted?

NDA 2017 Paper 1

MCQ (Single Correct Answer)

+2.5

-0.83

The mean weight of 150 students in a certain class is 60 kg. The mean weight of boys in the class is 70 kg and that of girls is 55 kg. What is the number of boys in the class?

100

NDA 2017 Paper 1

MCQ (Single Correct Answer)

+2.5

-0.83

If two regression lines between height (x) and weight (y) are 4y $$-$$ 15x + 410 = 0 and 30x $$-$$ 2y $$-$$ 825 = 0, then what will be the correlation coefficient between height and weight?

$${1 \over 3}$$

$${1 \over 2}$$

$${2 \over 3}$$

$${3 \over 4}$$

NDA 2017 Paper 1

MCQ (Single Correct Answer)

+2.5

-0.83

In an examination, 40% of candidates got second class. When the data are represented by a pie chart, wheat is the angle corresponding to second class?

40$$^\circ$$

90$$^\circ$$

144$$^\circ$$

320$$^\circ$$

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