Jack H.

asked • 06/20/15

Probability Help!

1. Use the frequency distribution to find the expected value (mean), variance, and the standard deviation. Number of downloads (X) 27 28 30 31 32 Probability (P(X)) 0.15 0.2 0.3 0.25 0.1
2. You have $10,000 to invest. After some investigating, you found two investment opportunities. Bond A has a return of 6.5% with a default rate of 2%. Bond B has a return of 8% with a default rate of 4%. Find the value of return and decide which bond would be a better investment.
3. Your statistics instructor will give you a quiz next class. The quiz has 10 questions, each with 4 choices (a, b, c, or d). You feel tired and do not study and decide to guess all the answers. What is the probability of passing this quiz? (Assume a passing grade is 7 correct questions)
4. If a distribution follow the binomial distribution with n=45 and probability of success of 0.78, find the mean and variance.
5. A brand has a recognition rate of 85%. If the corporate office wants to verify this rate with a sample of 30 randomly selected customers, find the probability that exactly 26 people recognize the brand name

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