Statistics and Probability MCQs | STA301 MCQs | Set 10
Statistics and Probability MCQs | STA301 MCQs | Set 10
MCQs (Multiple Choice Questions)
1) If A = {1,2,3,4} and B = {3,4,5,6} then A - B will be:
a) {1,2}
b) {3,4}
c) {3,2,1}
d) {1,2,3,4,5,6}
Correct Answer:
The correct answer is 'a'.
Explanation:
When you subtract set B from set A, (A - B), you are essentially removing the elements that are common to both sets. In this case, the common elements are 3 and 4. So, subtracting {3, 4} from {1, 2, 3, 4} results in {1, 2}.
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2) If P (B|A) = 0.25 and P (A and B) = 0.20, then P (A) is:
a) 0.05
b) 0.80
c) 0.95
d) 0.75
Correct Answer:
The correct answer is 'c'.
Explanation:
To find P(A), you can use the formula for conditional probability:
P(B|A) = P(A and B) / P(A)
Given P(B∣A) = 0.25 and P(A and B) = 0.20, you can rearrange the formula to solve for P(A):
P(A) = P(A and B) / P(B|A)
Substitute the values:
P(A) = 0.20/0.25 = 0.80
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3) According to Empirical rule, approximately 68% of the measurements will fall within:
a) (Mean - S.D, Mean + S.D)
b) (Mean - 2S.D, Mean + 2S.D)
c) (Mean - 3S.D, Mean + 3S.D)
d) None of these
Correct Answer:
The correct answer is 'a'.
Explanation:
According to the Empirical Rule (also known as the 68-95-99.7 rule), approximately 68% of the measurements in a normally distributed dataset will fall within one standard deviation (S.D) of the mean. This corresponds to the range (Mean - S.D, Mean + S.D).
For (Mean - 2S.D, Mean + 2S.D), it's about 95% of the measurements, and for (Mean - 3S.D, Mean + 3S.D), it's about 99.7% of the measurements.
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4) For Platykurtic distribution, b2 (moment ration) will be:
a) Greater than 3
b) Less than 3
c) Equal to 3
d) Equal to zero
Correct Answer:
The correct answer is 'b'.
Explanation:
A platykurtic distribution is characterized by having thinner tails and a flatter peak compared to a normal distribution. This means that the distribution has fewer extreme values and less emphasis on the tails, resulting in a smaller value for the moment ratio 2 `b_2` .
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5) There are two broad categories of data, which are:
a) Weighted and Un-weighted
b) Grouped and Un-grouped
c) Qualitative and Quantitative
d) Primary and Secondary
Correct Answer:
The correct answer is 'c'.
Explanation:
Data can be broadly categorized into qualitative and quantitative types. Qualitative data refers to non-numeric information, often describing qualities or characteristics. Quantitative data, on the other hand, consists of numeric measurements or quantities.
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6) In a linear regression, Y= a+bX , the variable “Y” will always:
a) A random variable
b) A nonrandom variable
c) Qualitative variable
d) Quantitative variable
Correct Answer:
The correct answer is 'd'.
Explanation:
In the equation, Y=a+bX, "Y" represents the dependent variable, which is the outcome being predicted or explained. Since "Y" is a quantity that is being measured or predicted, it is considered a quantitative variable.
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7) In regression line Y= a+bX , X is called:
a) Dependent variable
b) Independent variable
c) Explained variable
d) Regressand
Correct Answer:
The correct answer is 'b'.
Explanation:
In the regression line Y=a+bX, "X" is referred to as the independent variable. This is the variable that is believed to influence or explain the changes in the dependent variable "Y".
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8) The extremely positively skewed curve is also known as:
a) Frequency curve
b) U-shaped curve
c) J-shaped curve
d) Reverse J-shaped curve
Correct Answer:
The correct answer is 'd'.
Explanation:
An extremely positively skewed curve is often referred to as a reverse J-shaped curve. This indicates that the distribution has a long tail extending to the right and most of the data points are concentrated on the left side of the curve.
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9) A list of 7 pulse rates is: 70, 64, 80, 74, 92, 96, 98. What is the median for this list?
a) 70
b) 80
c) 92
d) 98
Correct Answer:
The correct answer is 'b'.
Explanation:
To find the median of a list of numbers, you first need to arrange the numbers in ascending order:
64, 70, 74, 80, 92, 96, 98
Since there are 7 numbers in the list, the median will be the middle value. In this case, the middle value is the fourth number, which is 80.
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10) The value of `10C_9`
a) 45
b) 35
c) 30
d) 10
Correct Answer:
The correct answer is 'd'.
Explanation:
The value of "10C_9" refers to the combination of choosing 9 items from a set of 10 items without considering the order. It is calculated using the formula for combinations: nCr = n! / (r! * (n - r)!), where n is the total number of items and r is the number of items to be chosen.
In this case, 10C9 = 10! / (9! * (10 - 9)!) = 10 / 1 = 10.
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