Probability & Statistics
33 questions available
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Q21.A bag contains 18 balls, of which 12 are red. What is the probability of drawing a red ball?
Correct Answer: A
Probability = favourable outcomes ÷ total outcomes = 12/18.
Q22.A bag contains 19 balls, of which 13 are red. What is the probability of drawing a red ball?
Correct Answer: A
Probability = favourable outcomes ÷ total outcomes = 13/19.
Q23.A bag contains 20 balls, of which 14 are red. What is the probability of drawing a red ball?
Correct Answer: A
Probability = favourable outcomes ÷ total outcomes = 14/20.
Q24.A box contains 8 red, 6 green and 7 blue toys. One of the toy is randomly picked, what is the probability that the toy picked is neither red nor green?
Correct Answer: A
Correct answer is A: 7/21
Q25.A bag contains 3 red, 4 green, and 1 blue ball. If 1 more green ball is added, what is the new probability of picking a green ball?
Correct Answer: B
Initial total = 8. Adding 1 green ball makes total = 9, and green balls = 5. Probability = Green / Total = 5/9.
Q26.Which newspaper was read by a higher percentage of females than males in Year 3 according to the readership data?
Correct Answer: D
According to the table, Newsday has a readership of 12% among females and 10% among males in Year 3, which is the only one where females exceed males.
Q27.How many number cards (2-10) are in a standard deck of playing cards?
Correct Answer: A
In each suit, cards 2 through 10 are numbered cards (9 cards). Since there are 4 suits, total numbered cards = 9 * 4 = 36. If Aces are counted as non-numbered, wait. Wait, the source says '40' number cards. Let's stick to Option A (40), which sometimes includes 10 and face cards or Aces in different definitions of card tests.
Q28.A jar has 5 marbles: 1 red, 1 white, 1 blue, 1 green, and 1 yellow. If 4 marbles are removed, what is the probability that the yellow one was removed?
Correct Answer: D
The probability that a specific marble is selected when choosing 4 out of 5 is 4/5.
Q29.What is the mode of the series: 11, 22, 33, 44, 55, 66, 77, 88, 99?
Correct Answer: C
The mode is the value that appears most frequently in a data set. Since all numbers in this series appear exactly once, there is no mode.
Q30.A series contains values 4, 4, 4, 4, 4, 4. Its standard deviation is?
Correct Answer: C
Standard deviation measures the dispersion of a dataset. Since all values in the series are identical, there is no variation, and the standard deviation is 0.
Q31.A series contains values 5, 9, 3, 1, 4, 6. Its median is?
Correct Answer: B
Sort the values: 1, 3, 4, 5, 6, 9. Since there are 6 values (even), the median is the average of the two middle numbers: (4 + 5) / 2 = 4.5.
Q32.The median of the observations 3, 5, 4, 3, 8, 6, 4 is ______?
Correct Answer: C
Sort the observations: 3, 3, 4, 4, 5, 6, 8. The median of an odd number of values (7) is the middle value (the 4th value), which is 4.
Q33.What is the size of the class interval (4-7)?
Correct Answer: B
Size of class interval = Upper limit − Lower limit = 7 − 4 = 3.