Question

Reaction times are normally distributed with mean 100 seconds and standard deviation of 10 seconds.  

a) What is the probability that a randomly chosen individual has reaction time of more than 45 seconds?

b) In a random sample of 36 individuals from the above population of reaction times, what is the probability that the sample mean reaction time is more than 45 seconds

Answer 1

X : reaction times.

X ~ N (100,10)

a).the probability that a randomly chosen individual has reaction time of more than 45 seconds is :-

[ in any blank cell of excel type =NORMSDIST(-5.5)]

b).sample size(n)= 36

the sample mean will follow normal distribution with:-

the probability that the sample mean reaction time is more than 45 seconds is:-

[ in any blank cell of excel type =NORMSDIST(-33)]

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