MCQ

Kindly highlight the correct answer

Question 21

A chi-square test involves a set of counts called "expected counts." What are the expected counts?

Select one:

Hypothetical counts that would occur if the null hypothesis were true.

Hypothetical counts that would occur of the alternative hypothesis were true.

The long-run counts that would be expected if the observed counts are representative.

The actual counts that did occur in the observed data.

Question 22

A company currently uses Brand A lightbulbs, which have a mean life of 1,000 hours. A salesperson marketing Brand B, a new brand of bulb, contacts the company. The company will switch to the new brand of bulb only if there is convincing evidence that the mean life of Brand B is greater than 1,000 hours. Which of the following hypotheses should the company test?

Select one:

H0: The mean life of Brand A bulbs is equal to the mean life of Brand B bulbs; H1: The mean life of Brand A bulbs is not equal to the mean life of Brand B bulbs.

H0: The mean life of Brand B bulbs is 1,000 hours; H1: The mean life of Brand A bulbs is less than 1,000 hours.

H0: The mean life of Brand A bulbs is 1,000 hours; H1: The mean life of Brand A bulbs is more than 1,000 hours.

H0: The mean life of Brand B bulbs is 1,000 hours; H1: The mean life of Brand B bulbs is more than 1,000 hours.

Question 23

In order to use the standard normal distribution you need to transform the scores in the sample to the standard normal scores. This is achieved by which of the following?

Select one:

Subtracting the mean from the standard deviation and then dividing by each score

Subtracting the score from the standard deviation and then dividing by the mean of each score

Subtracting the mean from each score and then dividing by the standard deviation

Subtracting the score from each mean and then dividing by the standard deviation

Question 24

The heights of 100 students are normally distributed with a mean of 172cm. What is the standard deviation of the heights given that the probability of a height above 185cm is 0.15?

Select one:

-33.73

12.64

33.7

-12.64

Question 25

A police officer is using a radar device to check motorists' speeds along Nairobi-Nakuru highway. Prior to beginning the speed check, the officer estimates that 40 percent of motorists will be driving more than 5 miles per hour over the speed limit. Assuming that the police officer's estimate is correct, what is the probability that among 4 randomly selected motorists, the officer will find at least 1 motorist driving more than 5 miles per hour over the speed limit?

Select one:

0.8704

0.3456

0.4752

0.1296

Question 26

The horizontal line in the control chart which shows the minimum value of a quality characteristic, before the process gets out-of-control, is called the _____

Select one:

Desired value

Lower control limit line

Center line

Upper control limit line

Question 27

What is distribution of values taken by a statistic in all possible samples of the same size from the same population called?

Select one:

The sampling distribution of the statistic.

The variance of the values.

The probability that the statistic is obtained.

The population parameter.

Question 28

If a probability distribution is symmetric, which of the following statements must be true?

Select one:

The distribution is uniform.

The distribution is bimodal.

The distribution is normal.

The mean of the distribution is equal to the median of the distribution

Question 29

Based on previous research, the standard deviation of the distribution of the age at which children begin to walk is estimated to be 1.5 months. A random sample of children will be selected, and the age at which each child begins to walk will be recorded. A 99 percent confidence interval for the average age at which children begin to walk will be constructed using the data obtained from the sample of children. Of the following, which is the smallest sample size that will result in a margin of error of 0.1 month or less for the confidence interval?

Select one:

609

865

1493

1218

Question 30

What is one of the distinctions between a population parameter and a sample statistic?

Select one:

A population parameter is only based on conceptual measurements, but a sample statistic is based on a combination of real and conceptual measurements.

A population parameter changes each time you try to measure it, but a sample statistic remains fixed across samples.

The true value of a sample statistic can never be known but the true value of a population parameter can be known.

A sample statistic changes each time you try to measure it, but a population parameter remains fixed.