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Suppose that 25% of US males and 23% of US females never eat breakfast. Suppose a random sample of 250 men and 250 women is taken and polled about eating breakfast.
a) What is the probabilty that at least 110 of these 500 people never eat breakfast?
b) What is the probability that the number of women who never eat breakfast is at least as large as the number of men who never eat breakfast?
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Binomial Distributions are investigated. The solution is detailed and well presented. The response received a rating of "5" from the student who originally posted the question.
- BSc , Wuhan Univ. China
- MA, Shandong Univ.
- "Your solution, looks excellent. I recognize things from previous chapters. I have seen the standard deviation formula you used to get 5.154. I do understand the Central Limit Theorem needs the sample size (n) to be greater than 30, we have 100. I do understand the sample mean(s) of the population will follow a normal distribution, and that CLT states the sample mean of population is the population (mean), we have 143.74. But when and WHY do we use the standard deviation formula where you got 5.154. WHEN & Why use standard deviation of the sample mean. I don't understand, why don't we simply use the "100" I understand that standard deviation is the square root of variance. I do understand that the variance is the square of the differences of each sample data value minus the mean. But somehow, why not use 100, why use standard deviation of sample mean? Please help explain."
- "excellent work"
- "Thank you so much for all of your help!!! I will be posting another assignment. Please let me know (once posted), if the credits I'm offering is enough or you ! Thanks again!"
- "Thank you"
- "Thank you very much for your valuable time and assistance!"
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