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victus00 [196]
3 years ago
14

Few students manage to complete their schooling without taking a standardized admissions test such as the Scholastic Achievement

Test, or SAT (used for admission to college); the Law School Admissions Test, or LSAT; and the Graduate Record Exam, or GRE (used for admission to graduate school). Sometimes, these multiple-choice tests discourage guessing by subtracting points for wrong answers. In particular, a correct answer will be worth +1 point, and an incorrect answer on a question with five listed answers (a through e) will be worth −1/4 points.
What is the expected value of eliminating one answer and guessing among the remaining four possible answers?
What is the expected value of eliminating three answers and guessing between the remaining two possible answers?
Mathematics
1 answer:
slega [8]3 years ago
6 0

Answer:

Step-by-step explanation:

Assuming there is a punitive removal of one point for an incorrect response.

Five undiscernable choices: 20% chance of guessing correctly -- Expectation: 0.20*(1) + 0.80*(-1) = -0.60

Four undiscernable choices: 25% chance of guessing correctly -- Expectation: 0.25*(1) + 0.75*(-1) = -0.50

I'll use 0.33 as an approzimation for 1/3

Three undiscernable choices: 33% chance of guessing correctly -- Expectation: 0.33*(1) + 0.67*(-1) = -0.33 <== The approximation is a little ugly.

Two undiscernable choices: 50% chance of guessing correctly -- Expectation: 0.50*(1) + 0.50*(-1) = 0.00

And thus we see that only if you can remove three is guessing neutral. There is no time when guessing is advantageous.

One Correct Answer: 100% chance of guessing correctly -- Expectation: 1.00*(1) + 0.00*(-1) = 1.00

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Zoe is 16 years old. Her brother, Luke, is 3 years more than half her age. Write a numerical expression for Luke's age.
olga nikolaevna [1]

Answer:

<u><em>16 : 2 + 3 </em></u>  (remember pemdas)

Step-by-step explanation:

Zoe is 16 years old. Her brother, Luke, is 3 years more than half her age. Write a numerical expression for Luke's age.

16 : 2 + 3 = 11

8 0
2 years ago
What is 11.876 rounded to the nearest tenth?
vesna_86 [32]

Answer:

11.9

Step-by-step explanation:

The tenth place is the first decimal. You round down from 1-4 and up from 5-9, so round up.

11.9

3 0
3 years ago
Read 2 more answers
Please help me. !no links or files! please and thank you :))
almond37 [142]

Answer:

7x+8m+7

Step-by-step explanation:

2(3x+4m)+x+7 =

6x+8m+x+7=

7x+8m+7

6 0
3 years ago
Read 2 more answers
The compressive strength of concrete is normally distributed with mu = 2500 psi and sigma = 50 psi. A random sample of n = 8 spe
Nata [24]

Answer:

X \sim N(2500,50)  

Where \mu=2500 and \sigma=50

We select a sample size of n =8. Since the distribution for X is normal then we know that the distribution for the sample mean \bar X is given by:

\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})

And the standard error would be:

SE = \frac{50}{\sqrt{8}}= 17.678 psi

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Solution to the problem

Let X the random variable that represent the compressive strength of concrete of a population, and for this case we know the distribution for X is given by:

X \sim N(2500,50)  

Where \mu=2500 and \sigma=50

We select a sample size of n =8. Since the distribution for X is normal then we know that the distribution for the sample mean \bar X is given by:

\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})

And the standard error would be:

SE = \frac{50}{\sqrt{8}}= 17.678 psi

7 0
3 years ago
Which equation goes with the t-chart below?
N76 [4]

Answer:

y = 2 x^2 + 5

Step-by-step explanation:

y = 2x^2 + 5

y = 2(-2)^2 + 5

y= 2(4) + 5

y = 8 + 5

y = 13

you can try for yourself using the other values

5 0
3 years ago
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