1 A student takes a quiz that consists of 190 questions wher

1) A student takes a quiz that consists of 190 questions, where he guesses on each questions. According to the given information, which of the following is the mean value of correct answers?

A)190

B) 50

C) 95

D) 90

2) If the areas of 40 cities added to a country of 50 cities and the total area is divided by 50, the result equals to 105,671 km².Which of the following statement is true corresponding to the result?

A)It is a statistic so that it shows some characteristic of a sample.

B)It is a parameter so that it shows some characteristic of a sample.

C)It is a statistic so that it shows some characteristic of a population.

D)It is a parameter so that it shows some characteristic of a sample.

3) Does the result appear to be a normal distribution?

A)No, because the histogram is uniform.

B)No, because the histogram is not symmetric.

C)Yes, the histogram is normal.

D)No, because histogram has no obvious maximum.

Solution

1) Prob of right answer on guess =0.5

so, E[X]= 190*0.5 =95

2)

it is a parameter and it reperesents sample characteristic and not poplation . The reason being , statistic is a Random variable while here it is fixed.

3)

here you have not provided any histogram, but notice the changes in the frequency

if the height is same then choose (a)

the histogram has to be symmetric for it to be normal but not exact it may be approx symmetic and so on.