Statistics - Probability & z-score

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Homework Help Overview

The discussion revolves around a statistics problem involving probability and z-scores, specifically focusing on the average time spent on Facebook and comparing individual versus group statistics.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants explore the implications of selecting a random individual versus a group of 35 people, questioning how the sample size affects probability. There is also a discussion about the calculation of z-scores and the criteria for determining the top 5% of users based on time spent on Facebook.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the problem's constraints and the necessary calculations. Some guidance has been offered regarding sample sizes, but no consensus has been reached on the interpretation of the problem.

Contextual Notes

Participants note that the problem lacks specific details about the second group, which contributes to the confusion in addressing the question.

charr1010
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The average amount of time people spend on facebook each day is 64 minutes, with a standard deviation of 4.5 minutes. Are you more likely to select a random person that spends less than 62 minutes per day, or a group of 35 people that spend on average less than 62 minutes per day on facebook? How many minutes would a person have to be on facebook to be considered the top 5%?


Z= X - M / SD

I am pretty sure this is the formula to use for this problem. I just got confused with what the number of people would be for the first half of the problem, the random person, because it is not given. If anyone can point me in the right direction it would be greatly appreciated. Thank you very much.
 
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You are comparing two experiments. One has 35 people in it. How many does the other have in it?
 
That lies the problem. What is written is all that is given for the problem and that is also why I am having such difficulty.
 
If you pick 35 random people out of the population, the size of your sample is 35.
If you pick one random person out of the population, the size of your sample is... one.
 

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