Sum Or Differences Of Variances Of Random Variables MCQ Tests
12th Class Statistics MCQ Tests
Sum Or Differences Of Variances Of Random Variables
of 12th Class Statistics has 5 questions. If you take an online MCQ test, the system will randomly choose the questions. If you want to take the quiz by chapter then click the start test button.
Total Questions: 5
Total Marks: 5
Time: 5 Mins
Total Questions: 5
Total Marks: 5
Time: 5 Mins
5Min : 00 Sec Remaining
Question # 1
Beth earns $25.00 an hour for tutoring but spends $20.00 an hour for piano lessons. She saves the difference between her earnings for tutoring and the cost of the piano lessons. The numbers of hours she spends on each activity in one week vary independently according to the probability distributions shown below. The standard deviation of hours Beth spends in one week on piano lessons and tutoring is 0.831 and 1.11 hours. Likewise, the expected number of hours Beth spends tutoring is 2.6 with the standard deviation of 1.11 hours. What is the standard deviation of her weekly savings is if she spends $20 for each hour of piano lessons, Beth earns $25 for each hour of tutoring.
Question # 2
The profit for a new product is given by Z=3X−Y−5, where X and Y are independent random variables with Var(X) = 1 and Var(Y) = 2. What is the variance of Z?
Question # 3
Consider the following probability distribution:
Question # 4
An insurance policy pays a total medical benefit consisting of a part paid to the surgeon, X, and a part paid to the hospital, Y , so that the total benefit is X+Y. Suppose that Var(X) = 5, 000, Var(Y) = 10, 000, and Var(X + Y) = 17, 000. If X is increased by a flat amount of 100, and Y is increased by 10%, what is the variance of the total benefit after these increases?
Question # 5
Let X and Y be discrete random variables with joint mass function defined by f(x, y) = 1/4, and (x, y) ϵ {(0, 0),(1, 1),(1, -1),(2, 0)} , find Var(X - 2Y).
Total Questions
12345
Question # 1
Beth earns $25.00 an hour for tutoring but spends $20.00 an hour for piano lessons. She saves the difference between her earnings for tutoring and the cost of the piano lessons. The numbers of hours she spends on each activity in one week vary independently according to the probability distributions shown below. The standard deviation of hours Beth spends in one week on piano lessons and tutoring is 0.831 and 1.11 hours. Likewise, the expected number of hours Beth spends tutoring is 2.6 with the standard deviation of 1.11 hours. What is the standard deviation of her weekly savings is if she spends $20 for each hour of piano lessons, Beth earns $25 for each hour of tutoring.
Question # 2
The profit for a new product is given by Z=3X−Y−5, where X and Y are independent random variables with Var(X) = 1 and Var(Y) = 2. What is the variance of Z?
Question # 3
Consider the following probability distribution:
Question # 4
An insurance policy pays a total medical benefit consisting of a part paid to the surgeon, X, and a part paid to the hospital, Y , so that the total benefit is X+Y. Suppose that Var(X) = 5, 000, Var(Y) = 10, 000, and Var(X + Y) = 17, 000. If X is increased by a flat amount of 100, and Y is increased by 10%, what is the variance of the total benefit after these increases?
Question # 5
Let X and Y be discrete random variables with joint mass function defined by f(x, y) = 1/4, and (x, y) ϵ {(0, 0),(1, 1),(1, -1),(2, 0)} , find Var(X - 2Y).
Total Questions
12345
Statistics
- Representation and Exploration of Data
- Measure of Central Tendency or Averages
- Measures of Dispersion
- Index Numbers
- Regression and Correlation Analysis
- Analysis of Time Series
- Set Theory
- Introduction to Probability
- Random Variables and Distributions
- Binomial and Hypergeometric Distributions
- The Normal Distribution
- Sampling and Sampling Distributions
- Statistical Inference:Estimation
- Statistical Inference:Hypothesis Testing
- Association of Attributes
12th Class Online Classes 2026
Updated on: 10-05-2026
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Punjab 12th Class Statistics Sum Or Differences Of Variances Of Random Variables