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ASK THE PROFESSOR FORUM

Course Documents

Chapter 1 - Intro

Chapter 2 - Methods for Describing Sets of Data

Chapter 3 - Probability

Chapter 4 - Discrete Random Variables

Chapter 5 - Normal Random Variables

Chapter 6 - Sampling Distributions

Chapter 7 - Confidence Intervals

Chapter 8 - Tests of Hypothesis: One Sample

Chapter 9 - Confidence Intervals and Hypothesis Tests: Two Samples

Sample Exam I: Chapters 1 & 2

Sample Exam II: Chapters 3 & 4

Sample Exam III: Chapters 5 & 6

Sample Exam IV: Chapters 7 & 8

Ask the Professor Forum

Hello Professor,
I need help solving 49 in homework 5.4. I have: n=50. p=.25 q=.75
and I am solving P(x>35)

is this correct?
Please help. Thank you.

Posted to STATS 1 on Monday, November 4, 2013   Replies: 1


Professor Mcguckian
11/04/2013
8:10 PM EST

Hi Christina,

I believe you are a student in my course, so I do want to mention that you are not required to learn 5.4 in your course. However, you have started the problem incorrectly. The problem reads, "What is the probability that when making random guesses on a fifty question multiple choice exam, with four answer choices for each question, that you miss at least thirty-five of the questions?"

In this case, we are looking for at least which implies X is greater than or equal to 35 not just greater than 35. Also, your x here represents the number of missed questions, so p should equal the probability of an incorrect guess. That means p = 0.75 and q = 0.25. That is opposite of what you have typed above.

Sincerely,

Professor McGuckian

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