The bell curve or normal distribution is frequently used to model the probability of natural random events. The normal distribution $N(\mu,\sigma)$ is characterized by two parameters:

$\mu$ is the mean value

$\sigma$ is the standard deviation

The study times in hours for the final exam is modeled as a normal distribution N(24,4). We are required to find the percentage of students study 34 hours or more, or P(X>34).

The values for the cumulative probability are given by tables or digital means like Excel where we can get the left-tail or P(X<Xo). To compute the right-tail or P(X>Xo) we use this relation

$P(X>Xo) =1-P(X$

The Excel formula to find the left-tail cumulative probability is called

NORM.DIST(x,mean,standard_dev,cumulative)

To solve the question, we used:

NORM.DIST(34,24,4,TRUE)=0.9938

Thus:

$P(X>34) =1-P(X$

The percentage of students study 34 hours or more is 0.62%

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3 years ago

I need help with this question asap. can someone plz help me: ​

I need help with this question asap. can someone plz help me: