Math Problem Statement

A manufacturer of game controllers is concerned that their controller may be difficult for​ left-handed users. They set out to find lefties to test. Suppose that about 88​% of the population is​ right-handed. They select a sample of twelve customers at random in their stores. Complete parts a through e below. Question content area bottom Part 1 ​a) Find the mean and standard deviation of the number of​ right-handers in the group. The mean number of righties is

10.56. The standard deviation would be

1.13. ​(Type integers or decimals rounded to two decimal places as​ needed.) Part 2 ​b) What is the probability that they are not all​ right-handed? The probability that they are not all righthanded is

0.784. ​(Round to three decimal places as​ needed.) Part 3 ​c) What is the probability that there are no more than 10 ​righties? The probability that there are no more than 10 righties is

0.431. ​(Round to three decimal places as​ needed.) Part 4 ​d) What is the probability that there are exactly 6 of​ each? The probability that there are exactly 6 of each is

enter your response here ​(Do not round until the final answer. Then round to five decimal places as​ needed.)

Solution

To solve part d (the probability that there are exactly 6 right-handed and 6 left-handed people in the sample), we can model this as a binomial distribution problem, where the probability of success (being right-handed) is p=0.88p = 0.88, the probability of failure (being left-handed) is 1p=0.121 - p = 0.12, and the sample size is n=12n = 12.

The probability of exactly kk right-handed people in a sample of nn is given by the binomial probability formula:

P(X=k)=(nk)pk(1p)nkP(X = k) = \binom{n}{k} p^k (1 - p)^{n-k}

For this problem, we want to find P(X=6)P(X = 6), where XX is the number of right-handed people. This means:

P(X=6)=(126)(0.88)6(0.12)6P(X = 6) = \binom{12}{6} (0.88)^6 (0.12)^6

Now let's calculate this.The probability that there are exactly 6 right-handed and 6 left-handed people in the sample is approximately 0.001280.00128 (rounded to five decimal places).

Would you like more details or have any further questions?

Here are five related questions to explore:

  1. How would the probability change if the sample size increased to 20?
  2. What is the probability of having exactly 8 right-handed people in the sample of 12?
  3. Can we approximate this binomial distribution using a normal distribution?
  4. How does the mean number of right-handers change if the sample size is reduced to 10?
  5. What is the probability that more than 10 out of 12 people are right-handed?

Tip: The binomial distribution is ideal for modeling events with only two possible outcomes, such as success/failure or yes/no scenarios.

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Math Problem Analysis

Mathematical Concepts

Probability
Binomial Distribution
Statistics

Formulas

Mean of binomial distribution: μ = np
Standard deviation of binomial distribution: σ = sqrt(np(1-p))
Binomial probability formula: P(X = k) = (n choose k) p^k (1 - p)^(n-k)

Theorems

Binomial Theorem
Law of Large Numbers

Suitable Grade Level

Grades 11-12