Suppose you are told that the grades of the nal exam of your class follows a normal distribution. The average score is 65 and the variance is 12. What is the the probability of a random classmate getting a score more than 80?

0% probability of a random classmate getting a score more than 80

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean and standard deviation(which is the square root of the variance) , the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this question, we have that:

What is the the probability of a random classmate getting a score more than 80?

This is 1 subtracted by the pvalue of Z when X = 80. So

has a pvalue of 1

1 - 1 = 0

0% probability of a random classmate getting a score more than 80

d is the answer

step-by-step explanation: