MCQ

Kindly highlight the correct answer

Question 31

A study compared the language skills and mental development of two groups of 24-month-old children. One group consisted of children identified as talkative, and the other group consisted of children identified as quiet. The scores for the two groups on a test that measured language skills are shown table below.

Talkative

75

70

70

65

85

85

80

Quiet

80

75

65

70

90

90

75

Assuming that it is reasonable to regard the groups as simple random samples and that the other conditions for inference are met, what statistical test should be used to determine if there is a significant difference in the average test score of talkative and quiet children at the age of 24 months?

Select one:

A chi-square test of independence

A two-sample t-test for means

A two sample Z- test for means

A linear regression t-test

Question 32

The monthly rent was determined for each apartment in a random sample of 100 apartments in Kileleshwa area. The sample mean was Sh.82000 and the sample standard deviation was Sh. 25000. An approximate 95 percent confidence interval for the true mean monthly rent for the population of apartments from which this sample was selected is Sh.81500, Sh. 82500. Which of the following statements is a correct interpretation of the 95 percent confidence level?

Select one:

In this sample, about 95 percent of the 100 rental prices are between Sh.81500, Sh. 82500.

In repeated sampling, the method produces intervals that include the population mean approximately 95 percent of the time.

In this population, about 95 percent of all rental prices are between Sh.81500, Sh. 82500.

There is a probability of 0.95 that the true mean is between Sh.81500, Sh. 82500.

Question 33

When developing the interval estimate of any population parameter, the value which is added or subtracted from the point estimate is called

Select one:

Sampling error

Measurement error

Standard error

Margin of error

Question 34

A process is said to be in the statistical control if it operates with ______ of variation.

Select one:

Both chance and assignable causes

Neither chance nor assignable causes

Chance causes

Assignable causes

Question 35

Which statement is not true about the 95% confidence level?

Select one:

The probability that the true value of the population parameter falls between the bounds of an already computed confidence interval is roughly 95%.

If we consider all possible randomly selected samples of the same size from a population, the 95% is the percentage of those samples for which the confidence interval includes the population parameter.

The procedure that is used to determine the confidence interval will provide an interval that includes the population parameter with probability of 0.95.

Confidence intervals computed by using the same procedure will include the true population value for 95% of all possible random samples taken from the population.

Question 36

For any process, the sample ranges are: 1.2, 1.5, 1.1, 1.4, 1.5. The subgroup size is 5. What will be the UCL for the range chart?

You are givenD4=2.114, d2=2.326, A2=0.577, d3=0.864.

Select one:

1.15776

2.83276

0.77318

3.11684

Question 37

Pick the choice that best completes the following sentence. "If a relationship between two variables is called statistically significant, it means the investigators think the variables are

Select one:

very important".

related to the sample due to chance alone".

not related to the population represented by the sample".

related to population represented by the sample".

Question 38

A chocolate manufacturing company produces individually wrapped chocolate bars. The quality assurance manager for the company believes that the weight of the bars is approximately normally distributed with mean 720 milligrams (mg). If the manager's belief is correct, which of the following intervals of weights will contain the largest proportion of the bars in the distribution of weights?

Select one:

700 mg to 740 mg

620 mg to 660 mg

660 mg to 700 mg

740 mg to 780 mg

Question 39

A certain health survey reported that the proportion of employees with elevated blood pressure is 0.15. The Human Resources Director of a leading multinational company believes that the proportion of employees in her company with elevated blood pressure is less than 0.15. If a sufficiently large sample is selected to estimate the proportion of all employees in this company who have elevated blood pressure, which of the following tests is the most appropriate to investigate the director's belief?

Select one:

A chi-square test of association

A t-test for the mean

A Z-score for the difference of proportions

A Z-score for a proportion

Question 40

A random sample of 60 students one high school in Kenya resulted in a 95 percent confidence interval for the mean number of hours of sleep per day of (5.4, 7.3). Which of the following statement best describes this confidence interval?

Select one:

About 95 percent of all random samples of 60 students from this school would result in a 95 percent confidence interval that covered the population mean number of hours of sleep per day.

95 percent of the students in this school sleep between 5.4 and 7.3 hours per day

About 95 percent of all random samples of 60 students from this school would result in a 95 percent confidence interval of (5.4, 7.3).

95 percent of the students in this survey reported sleeping between 5.4 and 7.3 hours per day.

A student selected at random from this population sleeps between 5.4 and 7.3 hours per day for 95 percent of the time.