A humanities professor assigns letter grades on a test according to the following scheme. A: Top 12%12% of scores B: Scores below the top 12%12% and above the bottom 62%62% C: Scores below the top 38%38% and above the bottom 17%17% D: Scores below the top 83%83% and above the bottom 7%7% F: Bottom 7%7% of scores Scores on the test are normally distributed with a mean of 75.275.2 and a standard deviation of 9.89.8. Find the minimum score required for an A grade. Round your answer to the nearest whole number, if necessary.

The minimum score required for an A grade is 86.8.

Step-by-step explanation:

We are given that a humanities professor assigns letter grades on a test according to the following scheme. A: Top 12% of scores B: Scores below the top 12% and above the bottom 62% C: Scores below the top 38% and above the bottom 17% D: Scores below the top 83% and above the bottom 7% E: Bottom 7% of scores

Scores on the test are normally distributed with a mean of 75.2 and a standard deviation of 9.8.

Let X = Scores on the test

SO, X ~ N()

The z-score probability distribution is given by ;

                  Z = ~ N(0,1)

where, = mean score = 75.2

            = standard deviation = 9.8

Now, the minimum score required for an A grade to be in the top 12% of scores is given by ;

              P(X ) = 0.12   {where is the minimum score required}

             P( ) = 0.12

             P(Z ) = 0.12

Now, in z table we will find out that critical value of X for which the area is in top 12%, which comes out to be 1.1835.

This means;        

                              = 75.2 + 11.5983 = 86.8

Therefore, the minimum score required for the scholarship is 86.8.

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.

yes because they have the same amount of green and blur marbles.

step-by-step explanation: