Math Problem Statement

22​% of college students say they use credit cards because of the rewards program. You randomly select 10 college students and ask each to name the reason he or she uses credit cards. Find the probability that the number of college students who say they use credit cards because of the rewards program is​ (a) exactly​ two, (b) more than​ two, and​ (c) between two and five inclusive. If​ convenient, use technology to find the probabilities. Question content area bottom Part 1 ​(a) ​P(2)equals    0.298 ​(Round to the nearest thousandth as​ needed.) Part 2 ​(b) ​P(xgreater than​2)equals    enter your response here ​(Round to the nearest thousandth as​ needed.)

Solution

This is a binomial probability problem, where we are interested in the probability that a certain number of college students, out of a random sample, say they use credit cards because of the rewards program.

Given:

  • Probability p=0.22p = 0.22 (22% of students use credit cards due to rewards)
  • n=10n = 10 (you select 10 students)
  • Let XX be the number of students who use credit cards for rewards. Thus, XBinomial(n=10,p=0.22)X \sim \text{Binomial}(n=10, p=0.22).

The binomial probability formula is: P(X=k)=(nk)pk(1p)nkP(X = k) = \binom{n}{k} p^k (1-p)^{n-k} where (nk)\binom{n}{k} is the binomial coefficient.

Let's solve for each part:

(a) Probability of exactly 2 students saying they use credit cards for rewards: P(X=2)P(X = 2)

We are given the result: P(X=2)=0.298P(X = 2) = 0.298 (Rounded to the nearest thousandth).

(b) Probability that more than 2 students say they use credit cards for rewards: P(X>2)P(X > 2)

To calculate this, we find: P(X>2)=1P(X2)P(X > 2) = 1 - P(X \leq 2) where P(X2)P(X \leq 2) is the cumulative probability for X=0,1,2X = 0, 1, 2.

Let's calculate P(X>2)P(X > 2).The probability that more than 2 college students say they use credit cards because of the rewards program is approximately P(X>2)=0.383P(X > 2) = 0.383 (rounded to the nearest thousandth).

Would you like details or have any questions? Here are five related questions for further practice:

  1. What is the probability that no students use credit cards for the rewards program?
  2. How would the probabilities change if you selected 20 students instead of 10?
  3. What is the expected number of students out of 10 who use credit cards for rewards?
  4. How would you calculate the variance of the binomial distribution in this context?
  5. What is the probability that exactly 5 students use credit cards for rewards?

Tip: In binomial problems, calculating cumulative probabilities P(Xk)P(X \leq k) helps solve for probabilities involving "less than" or "greater than" scenarios.

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Math Problem Analysis

Mathematical Concepts

Probability
Binomial Distribution

Formulas

P(X = k) = C(n, k) * p^k * (1 - p)^(n - k)
P(X > k) = 1 - P(X <= k)

Theorems

Binomial Theorem
Cumulative Probability Theorem

Suitable Grade Level

Grades 10-12