Statistics and Probability MCQs | STA301 MCQs | Set 6
Statistics and Probability MCQs | STA301 MCQs | Set 6
MCQs (Multiple Choice Questions)
1) Given the series 1, 2, 1, 1, 2, 2, 2, 2, 3, 4, 5, 3, 2, 3, 1, 4, 2, 3. Which one of the following is mode of the given series:
a) 4
b) 3 3
c) 2 3 2
d) 1 3 2*
Correct Answer:
The correct answer is 'd'.
Explanation:
To find the mode of a series, we need to determine the value or values that appear most frequently. Let's analyze the given series:
1, 2, 1, 1, 2, 2, 2, 2, 3, 4, 5, 3, 2, 3, 1, 4, 2, 3
Counting the occurrences of each value, we have:
1: 4 times
2: 5 times
3: 4 times
4: 2 times
5: 1 time
The mode is the value(s) with the highest frequency. In this case, both 2
and 1 appear the most frequently with a count of 5, so the mode is
either 2 or 1.
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2) Which one of the following is equal to the 2nd quartile:
a) `P_33`
b) `D_3`
c) Median
d) Mode
Correct Answer:
The correct answer is 'c'.
Explanation:
The second quartile, also known as the median, divides a dataset into two
equal halves. It represents the value below which 50% of the data
falls. Therefore, the second quartile is equal to the median.
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3) The variance of a sample of 81 observations is equal to
64. The standard deviation of the sample is equal to:
a) 256
b) 4096
c) 8
d) 6561
Correct Answer:
The correct answer is 'c'.
Explanation:
To find the standard deviation of a sample, you need to take the square
root of the variance. Given that the variance is 64, the
standard deviation is equal to the square root of 64, which is
8.
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4) Under which condition standard deviation could assume a negative
value:
a) When more than half of the data values are
negative
b) If all the data values are same
c) The standard deviation cannot be negative
d) When all the data values are negative
Correct Answer:
The correct answer is 'c'.
Explanation:
Standard deviation is a measure of dispersion or spread in a dataset. It
is always a non-negative value. The standard deviation cannot be
negative because it is calculated by taking the square root of the
variance, which is the average of squared differences from the mean.
Squaring the differences ensures that they are positive, and taking
the square root makes the standard deviation non-negative.
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5) In a set of 10 values all the values are 5, what will be the `D_5`?
a) 2
b) 5
c) 2 5 10
d) 20
Correct Answer:
The correct answer is 'b'.
Explanation:
In a set of 10 values where all the values are 5, the entire dataset consists of the value 5 repeated 10 times. Since all the values are the same, the 5th decile, or D_5, will also be 5.
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6) When three coins are tossed simultaneously, P (3 Heads) is:
a) `3/8`
b) `1/8`
c) `4/8`
d) `2/8`
Correct Answer:
The correct answer is 'b'.
Explanation:
When three coins are tossed simultaneously, there are a total of 8 possible outcomes: HHH, HHT, HTH, THH, HTT, THT, TTH, and TTT, where H represents heads and T represents tails.
Out of these 8 outcomes, only one outcome results in getting 3
heads:
HHH.
Therefore, the probability of getting 3 heads (P(3 Heads)) is
`1/8`.
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7) The distribution is mesokurtic if the moment ratio i.e. `b_2` is:
a) Equal to 0
b) Equal to 3
c) Less than 3
d) Greater than 3
Correct Answer:
The correct answer is 'b'.
Explanation:
The kurtosis of a distribution is measured by the moment ratio `b_2`.
A mesokurtic distribution refers to a distribution that has the same kurtosis as the normal distribution. The kurtosis of a normal distribution is 3.
Therefore, the moment ratio `b_2` for a mesokurtic distribution is 3.
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8) A set is any well-defined collection of
a) Positive Objects
b) Negative Objects
c) Samee Objects
d) Distinct Objects
Correct Answer:
The correct answer is 'd'.
Explanation:
In set theory, a set is a collection of distinct elements or objects. Each element in a set is unique and is not repeated within the set. Sets can contain objects of various types, such as numbers, letters, or even other sets.
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9) If an observation in the data set is negative, then the geometric mean is:
a) Positive
b) Negative
c) Zero
d) Undetermined
Correct Answer:
The correct answer is 'd'.
Explanation:
The geometric mean of a dataset is a measure of central tendency that is calculated by taking the nth root of the product of the dataset values, where n is the number of observations.
Since the geometric mean involves taking roots, it is not
defined for negative numbers. Therefore, if there is at
least one negative observation in the dataset, the
geometric mean is
undefined or "undetermined."
Therefore, the correct answer is Undetermined.
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10) For a positively skewed distribution `m_3` will be:
a) Positive
b) Negative
c) Zero
d) 1
Correct Answer:
The correct answer is 'a'.
Explanation:
For a positively skewed distribution, the third moment, denoted as `m_3`, will be positive.
Skewness is a measure of the asymmetry of a distribution. Positive skewness indicates that the tail of the distribution is skewed to the right, meaning there are more values on the left side and a few extreme values on the right side.
The third moment (`m_3`) is used to quantify the skewness of a distribution. If the distribution is positively skewed, `m_3` will have a positive value.
Therefore, the correct answer is Positive.
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