The time for a professor to grade an exam is normally distributed with a mean of 16.3 minutes and a standard deviation of 4.2 minutes. What is the probability that a randomly selected exam will require less than 20 minutes to grade

81.06% probability that a randomly selected exam will require less than 20 minutes to grade

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean and standard deviation , 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 problem, we have that:

What is the probability that a randomly selected exam will require less than 20 minutes to grade

This is the pvalue of Z when X = 20.

has a pvalue of 0.8106

81.06% probability that a randomly selected exam will require less than 20 minutes to grade

Answer

I The Turner family spent at least $100 each week.

A) I only

Step by step explanation

By looking at the graph. We can interpret the following information.

1st week = $145

2nd week = $105

3rd week = $125

4th week = $200

5th week = $150

From the above information.

The Turner family spent at least $100 each week.

The other statements are false.

Therefore, the answer A) I only

Thank you. :)