Answer:
The teacher should set the score 7 as the lowest passing grade.
Step-by-step explanation:
Let <em>X</em> = number of correct guesses.
All the questions are of true-false format.
The probability of getting a correct answer is, <em>p</em> = 0.50.
The total number of questions is, <em>n</em> = 10.
The random variable <em>X</em> follows a Binomial distribution with parameters <em>n</em> = 10 and <em>p </em>= 0.50.
The probability mass function of <em>X</em> is:
Now the teaches chose the grading scheme such that the probability of passing a student who guesses on every question is less than 0.05.
Then the probability of failing such a students is at least 1 - 0.05 = 0.95.
Compute the probability distribution of <em>X</em>.
Consider the probability distribution attached below.
The value of <em>x</em> for which P (X ≤ x) is at least 0.95 is, <em>x</em> = 7.
So the teacher should set the score 7 as the lowest passing grade.
7/12 14/24 21/36 28/48 35/60
Answer:
-1.575, or -1 575/1000, or -1 23/40
Step-by-step explanation:
Simplify the problem slightly by prefacing it with " - " as follows:
334
- ----------- = -1.575 = -1 23/40
212
Answer:
5.66 years
Step-by-step explanation:
450 x 1.025^(n) = 450 + 67.50
450 x 1.025^(n) = 517.50
1.025^(n) =(517.50 / 450)
1.025^(n) = 1.15
n = ln(1.15) / ln(1.025)
n = 5.66
9514 1404 393
Answer:
(a) 1. Distributive property 2. Combine like terms 3. Addition property of equality 4. Division property of equality
Step-by-step explanation:
Replacement of -1/2(8x +2) by -4x -1 is use of the <em>distributive property</em>, eliminating choices B and D.
In step 3, addition of 1 to both sides of the equation is use of the <em>addition property of equality</em>, eliminating choice C. This leaves only choice A.
_____
<em>Additional comment</em>
This problem makes a distinction between the addition property of equality and the subtraction property of equality. They are essentially the same property, since addition of +1 is the same as subtraction of -1. The result shown in Step 3 could be from addition of +1 to both sides of the equation, or it could be from subtraction of -1 from both sides of the equation.
In general, you want to add the opposite of the number you don't want. Here, that number is -1, so we add +1. Of course, adding an opposite is the same as subtracting.
In short, you can argue both choices A and C have correct justifications. The only reason to prefer choice A is that we usually think of adding positive numbers as <em>addition</em>, and adding negative numbers as <em>subtraction</em>.
