11. In how many different ways can the letters of the word ‘QWERTY’ be arranged ?
(A) 360
(B) 540
(C) 720
(D) 1420
Answer:
(C) 720
Explanation:
The word has 6 distinct letters. They can be arranged in 6! (6 factorial) ways. 6 * 5 * 4 * 3 * 2 * 1 = 720.
12. A bag contains six eggs and eight potatoes. One article is drawn at random. What is the probability that the article drawn is potato?
(A) 1/8
(B) 6/8
(C) 4/7
(D) 2/7
Answer:
(C) 4/7
Explanation:
Total articles = 6 + 8 = 14. Probability of drawing a potato = 8 / 14. Simplifying the fraction gives 4/7.
13. The relationship between mean, median and mode is:
(A) Mode = 3 Median – 2 Mean
(B) Median = 2 Mean – 3 Mode
(C) Mode = 2 Mean – 3 Median
(D) Mean = 3 Median – 2 Mode
Answer:
(A) Mode = 3 Median – 2 Mean
Explanation:
Karl Pearson’s empirical relationship for moderately skewed distributions states that the Mode is equal to three times the Median minus two times the Mean.
14. Given Mean 30, Mode 30, the Median would be:
(A) 40
(B) 25
(C) 35
(D) 30
Answer:
(D) 30
Explanation:
In a perfectly symmetrical distribution, the Mean, Median, and Mode are all perfectly equal. Since Mean and Mode are both 30, the Median is also 30.
15. The value of coefficient of correlation lies between:
(A) -1 and 0
(B) 0 and 1
(C) -1 and 1
(D) -1 and 5
Answer:
(C) -1 and 1
Explanation:
The Pearson correlation coefficient (r) always mathematically falls in the range between -1 (perfect negative correlation) and +1 (perfect positive correlation).
