Probability And Hypothesis Testing
Questions and Answers
- 1.
What is the probability of getting a sum total of 5 when 2 fair dice are rolled?
- A.
8/36
- B.
5/18
- C.
4/12
- D.
4/36
Correct Answer
D. 4/36Explanation
Total number of possibilities:36 (6x6). Number of ways to get 5: 4 (2,3),(3,2),(1,4),(4,1)Rate this question:
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- 2.
There are only 5 seats available on a flight. There are 3 passengers waiting to be seated. How many ways can they be seated?
- A.
10
- B.
60
- C.
15
- D.
30
Correct Answer
B. 60Explanation
The question is asking for the number of ways the 3 passengers can be seated in the 5 available seats. This can be calculated using the formula for combinations, which is the number of ways to choose a certain number of items from a larger set without regard to the order. In this case, it would be 5 choose 3, which is equal to 5! / (3! * (5-3)!) = 5! / (3! * 2!) = (5 * 4 * 3 * 2 * 1) / ((3 * 2 * 1) * (2 * 1)) = 10. Therefore, there are 10 ways the passengers can be seated.Rate this question:
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- 3.
You were given 10 questions to answer in an interview. But you were asked to answer for only 5 of them. You can choose whichever you like. How many ways can you answer the interview?
- A.
252
- B.
50
- C.
128
- D.
500
Correct Answer
A. 252Explanation
In this question, you are given 10 questions to answer in an interview but you are only asked to answer 5 of them. The question is asking how many ways you can choose which questions to answer. This is a combination problem, where you need to choose 5 questions out of 10. The formula for combinations is nCr = n! / (r!(n-r)!), where n is the total number of items and r is the number of items to be chosen. Plugging in the values, we get 10C5 = 10! / (5!(10-5)!) = 252. Therefore, there are 252 ways to answer the interview.Rate this question:
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- 4.
Garrison Keeler starts his Radio Show by saying all the childeren in Lake Wobegon are above average? Is he making sense, statistically speaking?
- A.
Yes
- B.
No
Correct Answer
B. NoExplanation
Garrison Keillor's statement that all the children in Lake Wobegon are above average does not make sense statistically. In a normal distribution, the average represents the midpoint, with an equal number of individuals above and below it. Therefore, it is statistically impossible for all the children to be above average. This statement contradicts the fundamental principles of statistics and is logically flawed.Rate this question:
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- 5.
The HbA1C levels were collected from a sample of 100 subjects. The sample mean was 4.8%. The sample standard deviation was 3.2 %. What is the standard error.
- A.
32%
- B.
3.2%
- C.
0.32%
- D.
0.032%
Correct Answer
C. 0.32%Explanation
The standard error is a measure of the variability or dispersion of a sample mean. It is calculated by dividing the sample standard deviation by the square root of the sample size. In this case, the sample standard deviation is given as 3.2%, and the sample size is 100. Therefore, the standard error can be calculated as 3.2% / square root of 100, which simplifies to 3.2% / 10 = 0.32%.Rate this question:
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- 6.
For the above question. Write the lower end of the popoluation's 95% confidence interval range. (Write only the number upto two decimal places, do not include percentage sign or other special characters).
Correct Answer
4.17
4.16
4.18Explanation
The lower end of the population's 95% confidence interval range is represented by the smallest number in the given options, which is 4.16.Rate this question:
- 7.
You have to choose one among the following two lotteries. Each lottery has three equally likely possibilities. Which one would you pick? Lottery 1: $4000 $5000 $ 9000 Lottery:2 $2000 $5000 $11000
- A.
Lottery 1
- B.
Lottery 2
- C.
Cannot decide
Correct Answer
A. Lottery 1Explanation
Lottery 1 has a higher maximum payout of $9000 compared to Lottery 2's maximum payout of $11000. Since both lotteries have equally likely possibilities, it is more favorable to choose the lottery with the higher maximum payout. Therefore, the correct answer is Lottery 1.Rate this question:
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- 8.
You have to choose one among the following two lotteries. Each lottery has three equally likely possibilities. Which one would you pick? Lottery 1: $12000 $7000 $ 5000 Lottery:2 $ 4000 $6000 $11000
- A.
Lottery 1
- B.
Lottery 2
- C.
Cannot Decide
Correct Answer
A. Lottery 1Explanation
Lottery 1 has a higher maximum prize of $12,000 compared to the maximum prize of $11,000 in Lottery 2. Therefore, it is more advantageous to choose Lottery 1 as it offers the potential for a higher payout.Rate this question:
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- 9.
You have to choose one among the following two lotteries. Each lottery has three equally likely possibilities. Which one would you pick? Lottery 1: $ 5000 $ 9000 $ 4000 Lottery:2 $ 3000 $ 2000 $ 1000
- A.
Lottery 1
- B.
Lottery 2
- C.
Cannot Decide
Correct Answer
C. Cannot DecideExplanation
The given question provides two lotteries with three possible outcomes each. However, it does not provide any information about the individual's preferences, risk tolerance, or any other factors that would influence their decision. Without any additional context, it is impossible to determine which lottery the individual would choose. Therefore, the answer "Cannot Decide" is the most appropriate.Rate this question:
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- 10.
Check all that are true.
- A.
A distribution is equivalent to histogram
- B.
The Y-axis of a distribution shows actual frequency
- C.
The Y-axis of a distribution shows actual proportion of frequency
- D.
The X axis shows bins (categories) or real values
Correct Answer(s)
A. A distribution is equivalent to histogram
C. The Y-axis of a distribution shows actual proportion of frequency
D. The X axis shows bins (categories) or real valuesExplanation
A distribution is equivalent to a histogram because both represent the frequency or proportion of values within different categories or bins. The Y-axis of a distribution shows the actual proportion of frequency, as it represents the relative size of each category or bin compared to the total. The X-axis shows the bins or categories, which can be either discrete values or ranges in a histogram.Rate this question:
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- 11.
What is probability of getting a number between 3 and 5 from a random number uniformly distributed between -4 and +4.
- A.
0.5
- B.
0.2
- C.
0.1
- D.
Cannot be computed
Correct Answer
C. 0.1Explanation
The probability of getting a number between 3 and 5 from a random number uniformly distributed between -4 and +4 can be computed by finding the proportion of the total range that falls within the desired range. In this case, the desired range is 2 units wide (from 3 to 5) and the total range is 8 units wide (from -4 to 4). Therefore, the probability is 2/8, which simplifies to 0.25.Rate this question:
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- 12.
Check all that are true
- A.
A random number having distribution with greater spread has higher average.
- B.
A random number having distribution with greater spread has higher variance.
- C.
A random number having distribution with greater spread has higher standard deviation.
- D.
A random number having distribution with greater spread has higher median.
Correct Answer(s)
B. A random number having distribution with greater spread has higher variance.
C. A random number having distribution with greater spread has higher standard deviation.Explanation
A random number having distribution with greater spread has higher variance because variance measures the average squared deviation from the mean, and a greater spread means that the values are more dispersed from the mean. Similarly, a random number having distribution with greater spread has higher standard deviation because standard deviation is the square root of variance and it also measures the dispersion of the values from the mean.Rate this question:
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- 13.
Hypothesis testing allows us to
- A.
Extract new information
- B.
Test if the sample data supports or does not support a theory
- C.
Proove a theory
- D.
Disproove a theory
Correct Answer
B. Test if the sample data supports or does not support a theoryExplanation
Hypothesis testing is a statistical method used to determine whether the sample data provides evidence to support or reject a theory or hypothesis. It helps in evaluating the validity of a claim or assumption by analyzing the data and calculating the probability of obtaining the observed results by chance alone. By comparing the sample data with the expected outcomes under a given theory, hypothesis testing allows us to make informed decisions about the theory's validity.Rate this question:
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- 14.
Rejecting a null hypothesis means
- A.
Disproving a theory
- B.
Accepting a theory
- C.
It is unlikely that the theory holds given the sampled data
- D.
We do not accept the results
Correct Answer
C. It is unlikely that the theory holds given the sampled dataExplanation
Rejecting a null hypothesis means that there is enough evidence to suggest that the theory is unlikely to hold true based on the sampled data. It does not necessarily mean disproving the theory or accepting an alternative theory. It simply indicates that the data collected does not support the null hypothesis and suggests that there may be another explanation or factor at play.Rate this question:
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- 15.
A pharmaceutical company wants to obtain a patent for a drug it claims to reduce Systolic Blood Pressure among people aged between 40 and 60 years. The company conducted an elaborate clinical trails in this regard. Check all the scenarios where the company fails to obtain the required FDA approval.
- A.
There were only 500 patients.
- B.
Only 40% of the subjects showed actual reduction
- C.
Compared to the control group (people who did not take the drug), the treatment group (people who took the drug) showed no statistically significant reduction in SBP.
- D.
Nearly 90% of the patients are less than 50 years old
- E.
The company did not include paired t-test results.
Correct Answer(s)
C. Compared to the control group (people who did not take the drug), the treatment group (people who took the drug) showed no statistically significant reduction in SBP.
D. Nearly 90% of the patients are less than 50 years oldExplanation
The company fails to obtain the required FDA approval because the treatment group, which took the drug, did not show a statistically significant reduction in SBP compared to the control group, which did not take the drug. Additionally, nearly 90% of the patients are less than 50 years old, which may not align with the target age range of 40 to 60 years.Rate this question:
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- 16.
A normal distribution is preferred over uniform distribution.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
A normal distribution is not necessarily preferred over a uniform distribution. The choice between the two depends on the specific context and the characteristics of the data being analyzed. A normal distribution is often used when the data is expected to cluster around a central value, with fewer values at the extremes. On the other hand, a uniform distribution is used when all values are equally likely to occur within a given range. Therefore, the statement that a normal distribution is always preferred over a uniform distribution is false.Rate this question:
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- 17.
Are random numbers generated by computer truely random? Hint: Think of randomness as something we absolutely cannot predict
- A.
Yes
- B.
No
Correct Answer
B. NoExplanation
No, random numbers generated by a computer are not truly random. Computers use algorithms to generate random numbers, which means that the numbers are actually determined by a set of rules. While these algorithms can produce sequences of numbers that appear random, they are ultimately predictable. Therefore, the randomness generated by a computer is not absolute and can be predicted to some extent.Rate this question:
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- 18.
What is (x+1)! / (x-1)! ?
- A.
X^2
- B.
X/(X-1)
- C.
X*(X+1)
- D.
X
Correct Answer
C. X*(X+1)Explanation
The expression (x+1)! / (x-1)! can be simplified by canceling out the common terms in the numerator and denominator. The (x-1)! terms cancel out, leaving us with (x+1) * x. This can be further simplified to x * (x+1), which matches the given answer X*(X+1).Rate this question:
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Mar 21, 2023Quiz Edited by
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Jul 24, 2012Quiz Created by
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