A statistics teacher gives a multiple-choice exam with 20 questions. The teacher wants to discourage guessing on the exam, so for each question the student earns 1 point for a correct answer, 0 points for no answer, and -1 point for a wrong answer. Consequently, if a student answered every question incorrectly the student would earn a score of -20 on the exam. However, if a student answered every question correctly, the student would earn a score of 20 on the exam. After the exam, the teacher distributes the list of test scores and asks the class to calculate the standard deviation. The first student to finish the calculations says that the standard deviation is -1.8. a. True
b. False

b. False

Step-by-step explanation:

The answer is false because the standard deviation was miscalculated.

We can compute the formula for calculating the standard deviation as:

As a result of the  square in the numerator of the summation, the square   is usually non-negative.

Even if the data is positive, negative or zero, as a result of the above claim, the standard deviation is always non-negative.

Thus, the fact that the first student who finishes the calculation first and claim that the standard deviation is -1.8 is false.

i have no clue at all sorry

step-by-step explanation:

b: |12 – x| ≤ 0.25

step-by-step explanation:      

let x be the possible lengths in inches, of the ribbons jaime cut.

we have been given that jaime is cutting strips of ribbon for a project. he tries to cut each piece to be 12 inches long, but sometimes he cuts it too long or too short by as much as 0.25 inch.  

we can represent this information in an inequality as:

by the definition of absolute value function we will get,

upon combining our inequalities we will get,

therefore, the inequality   describes all the possible lengths (x), in inches, of the ribbons jaime cut.

step-by-step explanation: