Can you help me solve this

You are to take a multiple-choice exam consisting of 64 questions with 5 possible responses to each question. Suppose that you h

damaskus [11]

Answer:

a) Expected score on the exam is 12.8.

b) Variance 10.24, Standard deviation 3.2

Step-by-step explanation:

For each question, there are only two possible outcomes. Either you guesses the answer correctly, or you does not. The probability of guessing the answer of a question correctly is independent of other questions. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

The expected value of the binomial distribution is:

$E(X) = np$

The variance of the binomial distribution is:

$V(X) = np(1-p)$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

64 questions.

So $n = 64$

5 possible answers, one correctly, chosen at random:

So $p = \frac{1}{5} = 0.2$

(a) What is your expected score on the exam?

$E(X) = np = 64*0.2 = 12.8$

(b) Compute the variance and standard deviation of x. Variance =Standard deviation

$V(X) = np(1-p) = 64*0.2*0.8 = 10.24$

Variance 10.24

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{64*0.2*0.8} = 3.2$

Standard deviation 3.2

5 0

3 years ago

Find the x- and y-intercepts of the function f(x) = log(2x + 1) − 1.

Vilka [71]

Answer:

(9/2,0) and (0,-1)

Step-by-step explanation:

y(0) = log(1)-1 = -1

y=0 when log(2x+1) = 1

2x+1 = 10

x = 9/2

6 0

3 years ago

A shipping carton in the shape of a rectangular prism has a volume of 756 cubic inches the base area of the shipping carton is 4

coldgirl [10]

The answer would be a height o 18 inches. how you figure that is by taking the total cubic inches and divide by the base number which is 42 inches. 756 divided by 42 is 18. and to check your answer multiply. 18 times 42 equals 756.

8 0

3 years ago

Read 2 more answers

Plzzzz help me plzzzzz z z z zz z !!!!!!!!!

denis-greek [22]

Answer:

circle: ( 1, 0.5 )

square: ( 4.5, 3.5 )

triangle: ( 0, 2.5 )

Step-by-step explanation:

4 0

2 years ago

A random sample of 20 houses selected from a city showed that the mean size of these houses is 1880 square feet with a standard

azamat

Answer:

Option C

Step-by-step explanation:

Given that for a random sample of 20 houses selected from a city showed that the mean size of these houses is 1880 square feet with a standard deviation of 320 square feet.

X, the sizes of houses is Normal

Hence sample mean will be normal with

Mean = 1880

and std dev = $\frac{320}{\sqrt{20} } \\=71.5542$

For 90% confidence interval critical value for t with degree of freedom 19 is

1.328

Confidence interval upper bound

= mean + margin of error

= $1880+1.328*71.55\\=1975$

Option C is right

3 0

3 years ago