MCQ

Please highlight the correct answer

Question 11

Assume the given distributions are normal. An electronic product takes an average of 3.4 hours to move through an assembly line. If the standard deviation is 0.5 hour, what is the probability that an item will take between 3 and 4 hours?

Select one:

0.8849303

0.6554217

0.6730749

0.2118554

Question 12

Past data has shown that the regression line relating the final exam score and the midterm exam score for students who take statistics from a certain lecturer is F=50+0.5m where F is the final exam score and m is the midterm exam score. One interpretation of the slope is

Select one:

a student who scored 0 on the midterm would be predicted to score 50 on the final exam

students only receive half as much credit (.5) for a correct answer on the final exam compared to a correct answer on the midterm exam

a student who scored 0 on the final exam would be predicted to score 50 on the midterm

a student who scored 10 points higher than another student on the midterm would be predicted to score 5 points higher than the other student on the final exam

Question 13

The lower control limit for the R-chart is given by ____

Select one:

D3*mean Range

D3*mean Range

d2*mean Range

D4*mean Range

Question 14

If the sample size is greater than or equal to 30 then the sample standard deviation is used as an estimate for the population standard deviation when

Select one:

central limit theorem is violated

standard deviation of the population is known

central limit theorem holds

standard deviation of the population is unknown

Question 15

A kidney dialysis center periodically checks a sample of its equipment and performs a major recalibration if readings are sufficiently off target. Similarly, a fabric factory periodically checks the sizes of towels coming off an assembly line and halts production if measurements are sufficiently off target. In both situations, we have the null hypothesis that the equipment is performing satisfactorily. For each situation, which is themoreserious concern, a Type I or Type II error?

Select one:

Dialysis center: Type I error, towel manufacturer: Type I error

Dialysis center: Type II error, towel manufacturer: Type II error

Dialysis center: Type II error, towel manufacturer: Type I error

Dialysis center: Type I error, towel manufacturer: Type II error

Question 16

A survey was recently conducted in which both men and women were asked a question about whether the government should implement a full lockdown in Nairobi in order to control the spread of the COVID-19. Possible responses to this question were "in favor of," "not in favor of," or "no opinion." A chi-square test was used to determine whether the response to this question is independent of gender. The number of degrees of freedom for the chi-square test in this situation is

Select one:

6

3

2

5

Question 17

A correlation between the grade obtained in K.C.S.E and scholastic achievement was found to be -1.28 by a certain university researcher. On the basis of this you would tell the university that:

Select one:

Students at this school are underachieving.

The grade obtained in K.C.S.E is a good predictor of academic success.

The grade obtained in K.C.S.E is not a good predictor of academic success.

They should hire a new researcher.

Question 18

A historian believes that the average height of soldiers in World War II was greater than that of soldiers in World War I. She examines a random sample of records of 100 men in each war and notes standard deviations of 2.5 and 2.3 inches in World War I and World War II, respectively. If the average height from the sample of World War II soldiers is 1 inch greater than from the sample of World War I soldiers, what conclusion is justified from a two-sample hypothesis test where H0:m1=m2 versus H0:m1

Select one:

A conclusion is not possible without knowing both the sample means and the two original population sizes

A conclusion is not possible without knowing the mean height in each sample.

The observed difference in average height is not significant at 5 percent level of significance.

The observed difference in average height is significant at 5 percent level of significance.

Question 19

Suppose you collected data on the diameter of tree trunks (in inches), X, the tree height (in feet), Y. If the fitted regression equation is Y=-3.6+3.1X, what is your estimate of the average height of all trees having a trunk diameter of 7 inches?

Select one:

21.1 ft

22.1 ft

18.1 ft

19.1 ft

Question 20

Which of the following is not a property of a binomial experiment?

Select one:

The trials are independent

The probabilities of the two outcomes can change from one trial to the next

The experiment consists of a sequence of n identical trials.

Each outcome can be referred to as a success or a failure.