7. To get the standard deviation take the square root of the variance. ASSESSMENT Instruction: Solve and interpret problems involving the mean, variance and standard deviation, a discrete random variable and probability distribution. (20 points) 1. A five-question quiz was given to students in a Statistics and Probability class. The random variable x denotes the number of correctly answered questions. What is the variance of the following probability distribution? (See example 3 on pages 14 and 15) 0 1 2 3 4 5 P(x) 0.07 0.08 0.16 0.21 0.25 0.23 Steps Solution 1. Find the mean of the probability distribution using the formula, H = [[xP(x)] 2. Substitute the given in the formula, o' =[[X P(x)] - H 3. Simplify values that have an exponent. 4. Multiply the results obtained in Step 3 and its corresponding probabilities. 5. Add the values obtained Step 4. 6. Subtract the square mean from the result obtained in Step 5. 18