2. The number of burgers (X) delivered to QU students each week has the followin

Question

2. The number of burgers (X) delivered to QU students each week has the following probability distribution X P(x) .3 .4 .2 3 If the burger shop makes a profit of 5 QR per burger, what is the mean and standard deviation of the profit per week? 3-A survey found that 40% of the students think that the Business Statistics course needs to be more challenging. If 25 of the students are randomly chosen, what is the probability that at least 11 of them would agree that Business Statistics course needs to be more challenging?

Explanation / Answer

2) mean (E(x)) = 0 * 0.1 + 1 * 0.3 + 2 * 0.4 + 3 * 0.2

= 1.7

E(x2) =   0^2 * 0.1 + 1^2 * 0.3 + 2^2 * 0.4 + 3^2 * 0.2 = 3.7

Variance = E(x2) - (E(x))2

= 3.7 - 2.89 = 0.81

Standard deviation = sqrt(0.81) = 0.9

Mean of profit = 5 * 1.7 = 8.5

Standard deviation of profit = 5 * 0.9 = 4.5

3) P = 0.4

n = 25

P(X = x) = nCx * Px * (1 - P)n - x

P(X > 11) = 1 - P (X < 11)

= 1 - (P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 9) + P(X = 10))

= 1 - (25C0 * (0.4)^0 * (0.6)^25 + 25C1 * (0.4)^1 * (0.6)^24 + 25C2 * (0.4)^2 * (0.6)^23 + 25C3 * (0.4)^3 * (0.6)^22 + 25C4 * (0.4)^4 * (0.6)^21 + 25C5 * (0.4)^5 * (0.6)^20 + 25C6 * (0.4)^6 * (0.6)^19 + 25C7 * (0.4)^7 * (0.6)^18 + 25C8 * (0.4)^8 * (0.6)^17 + 25C9 * (0.4)^9 * (0.6)^16 + 25C10 * (0.4)^10 * (0.6)^15

= 1 - 0.5858

= 0.4142

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.