STT206 TMA_3 SOLUTIONS


Question
You conduct a hypothesis test and you observe values for
 the sample mean and sample standard deviation when n = 25 that do not lead to the rejection of .
You calculate a p-value of 0.0667. What will happen to the p-value if you observe the same sample mean
and standard deviation for a sample > 25?

Answer
decrease



Question
For the chi-square test to be effective, the expected value for each cell in the contingency table has to be at least

Answer
5



Question
For t distribution, increasing the sample size, the affect will be on

Answer
All the options



Question
If we reject the null hypothesis, we might be making

Answer
TypeI Error



Question
In a regression, that the standard error of the regression is, the greater the accuracy of the prediction will be

Answer
Smaller



Question
A residual is defined as

Answer
\(Y-\widehat{Y}\)



Question
In regression analysis, the variable that is used to explain the change in the outcome of an experiment, or some natural process, is called

Answer
all of the above (a-c) are correct



Question
The regression line is drawn so that:

Answer
The sum of the squared errors is as small as possible



Question
The percent of total variation of the dependent variable Y explained by the set of independent variables X is measured by

Answer
Coefficient of Determination



Question
If the coefficient of determination is 0.81, the correlation coefficient

Answer
could be either \(+ 0.9 or - 0.9\)



Question
Suppose men always married women who were 10 percent shorter than they were. The correlation coefficient of the heights of married couples would be

Answer
1.0 since the height of the man is always predictable from the height of the woman



Question
We measure heights and weights of 100 twenty-year old male college students. Which will have the higher correlation

Answer
Both will have the same correlation



Question
Suppose the correlation coefficient between heights (as measured in feet) versus weight (as measured in pounds) is 0.40. What is the correlation coefficient of height measured in inches versus weight measured in ounces? [12 inches = one foot; 16 ounces = one pound]

Answer
0.4



Question
An investigator is studying the relation between the physical and intellectual growth of primary school children (grades 1-6). At each grade level, she notes that the correlation between the height of children and the size of their vocabulary is zero. For all students in the school, the correlation is likely to be

Answer
Positive



Question
A summary measure that describes any given characteristic of the population is known as a ___________

Answer
Parameter



Question
A _________ sample is formed by selecting one unit at random and then selecting additional units at evenly spaced intervals until the sample has been formed

Answer
Systematic



Question
Laspeyre’s index numbers possess ___________

Answer
Upward bias



Question
Most commonly used index number is____________

Answer
None



Question
Investor wishing to invest N100,000 in one of three possible investment alternatives, A, B, and C is an example of

Answer
Decision making under uncertainty



Question
The mean of a distribution is 23, the median is 24, and the mode is 25.5. It is most likely that this distribution is:

Answer
Negatively Skewed



Question
The mean of a distribution is 14 and the standard deviation is 5. What is the value of the coefficient of variation?

Answer
0.357



Question
The mean deviation of the series \(a, a + d, a +2d \cdots + 2n\) from its mean is

Answer
n (n +1) d /2n +1



Question
A student obtained the mean and the standard deviation of 100 observations as 40 and 5.1. It was later found that one observation was wrongly copied as 50, the correct figure being 40. Find the correct mean and the S.D

Answer
Mean = 39.9, S.D =5



Question
For a negatively skewed distribution, the correct inequality is____________

Answer
Mean


Question
What percentage of values is greater the 3rd quartile?

Answer
0.25



Question
Which of the following is a unit less measure of dispersion?

Answer
Coefficient of variation



Question
Individual data is another wise called as ___________

Answer
raw data



Question
The data given as 5, 7, 12, 17, 79, 84, and 91 will be called as____________

Answer
An individual series



Question
Which of the following example does not constitute an infinite population?

Answer
  Population of heights of 15 year old children.



Question
In a web-based survey, customers are asked to rate your company’s product on the following scale: Excellent, good, average, poor. The above scale is _____________________

Answer
ordinal



Question
You conduct a hypothesis test and you observe values for the sample mean and sample standard deviation when n = 25 that do not lead to the rejection of . You calculate a p-value of 0.0667. What will happen to the p-value if you observe the same sample mean and standard deviation for a sample > 25?

Answer
decrease



Question
For the chi-square test to be effective, the expected value for each cell in the contingency table has to be at least

Answer
5



Question
For t distribution, increasing the sample size, the affect will be on

Answer
All the options



Question
If we reject the null hypothesis, we might be making

Answer
TypeI Error



Question
In a regression, that the standard error of the regression is, the greater the accuracy of the prediction will be

Answer
Smaller



Question
A residual is defined as

Answer
\(Y-\widehat{Y}\)



Question
In regression analysis, the variable that is used to explain the change in the
outcome of an experiment, or some natural process, is called

Answer
all of the above (a-c) are correct



Question
The regression line is drawn so that:

Answer
The sum of the squared errors is as small as possible



Question
The percent of total variation of the dependent variable Y explained by the set of independent variables X is measured by

Answer
Coefficient of Determination



Question
If the coefficient of determination is 0.81, the correlation coefficient

Answer
could be either \(+ 0.9 or - 0.9\)



Question
Suppose men always married women who were 10 percent shorter than they were. The correlation coefficient of the heights of married couples would be

Answer
1.0 since the height of the man is always predictable from the height of the woman



Question
We measure heights and weights of 100 twenty-year old male college students. Which will have the higher correlation

Answer
Both will have the same correlation



Question
Suppose the correlation coefficient between heights (as measured in feet) versus weight (as measured in pounds) is 0.40. What is the correlation coefficient of height measured in inches versus weight measured in ounces? [12 inches = one foot; 16 ounces = one pound]

Answer
0.4



Question
An investigator is studying the relation between the physical and intellectual growth of primary school children (grades 1-6). At each grade level, she notes that the correlation between the height of children and the size of their vocabulary is zero. For all students in the school, the correlation is likely to be

Answer
Positive



Question
A summary measure that describes any given characteristic of the population is known as a ___________

Answer
Parameter



Question
A _________ sample is formed by selecting one unit at random and then selecting additional units at evenly spaced intervals until the sample has been formed

Answer
Systematic



Question
Laspeyre’s index numbers possess ___________

Answer
Upward bias



Question
Most commonly used index number is____________

Answer
None



Question
Investor wishing to invest N100,000 in one of three possible investment alternatives, A, B, and C is an example of

Answer
Decision making under uncertainty



Question
The mean of a distribution is 23, the median is 24, and the mode is 25.5. It is most likely that this distribution is:

Answer
Negatively Skewed



Question
The mean of a distribution is 14 and the standard deviation is 5. What is the value of the coefficient of variation?

Answer
0.357



Question
The mean deviation of the series \(a, a + d, a +2d \cdots + 2n\) from its mean is

Answer
n (n +1) d /2n +1



Question
A student obtained the mean and the standard deviation of 100 observations as 40 and 5.1. It was later found that one observation was wrongly copied as 50, the correct figure being 40. Find the correct mean and the S.D

Answer
Mean = 39.9, S.D =5



Question
For a negatively skewed distribution, the correct inequality is____________

Answer
Mean


Question
What percentage of values is greater the 3rd quartile?

Answer
0.25



Question
Which of the following is a unit less measure of dispersion?

Answer
Coefficient of variation



Question
Individual data is another wise called as ___________

Answer
raw data



Question
The data given as 5, 7, 12, 17, 79, 84, and 91 will be called as____________

Answer
An individual series



Question
Which of the following example does not constitute an infinite population?

Answer
  Population of heights of 15 year old children.



Question
In a web-based survey, customers are asked to rate your company’s product on the following scale: Excellent, good, average, poor. The above scale is _____________________

Answer
ordinal

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