Question 1

Sample values of 13 monthly sales figures (in thousands of dollars)are: 6,5,6,6,7,8,9,10,10,10,9,9,and 6.
What is the mean sales figure?
____________________ thousand

Accepted Answer

The answer of Sample values of 13 monthly sales figures...

Question 2

If the coefficient of correlation $ r=\pm 1 $ ,then the best-fit linear equation will include:
A) 75% of the data points.
B) 85% of the data points.
C) 95% of the data points.
D) all of the data points.

Accepted Answer

If the coefficient of correlation $r=\pm 1$, it means there is a perfect linear relationship between the two variables. In other words, all the data points lie exactly on a straight line. Therefore, the best-fit linear equation will include all the data points.

Question 3

The average profit per unit for Product A is $5.32,Product B is $7.98,and Product C is $9.69.If the percentages of each sold are 36,29,and 35 respectively,what is the weighted mean profit per unit?

Accepted Answer

The answer of The average profit per unit for Product...

Question 4

For a set of data,the mean is 50 and the standard deviation is 10.In the raw data,one of the observations is equal to 74.After the data are standardized,what will be the standardized value of this observation?
A) +7.4
B) -7.4
C) +2.4
D) -2.4

Accepted Answer

To standardize the data, we use the formula: 
z = (x - μ) / σ
where z is the standardized value, x is the observation, μ is the mean, and σ is the standard deviation.

Plugging in the values, we get: 
z = (74 - 50) / 10
z = 2.4

Therefore, the standardized value of the observation 74 is +2.4.

Question 5

The length of the box in the box-and-whisker plot portrays the:
A) mean
B) median
C) range
D) interquartile range

Accepted Answer

The length of the box in a box-and-whisker plot represents the interquartile range, which is the range of values that contains the middle 50% of the data. The median is represented by a vertical line within the box, and the range is shown by the whiskers (lines or bars extending from the box). The mean is not typically included in a box-and-whisker plot.

Question 6

If the coefficient of correlation r = 0,then:
A) the slope of the regression line is zero.
B) there is no linear relationship whatsoever between the dependent variable y and the independent variable x.
C) the coefficient of determination is zero.
D) All of these are correct.
E) None of these is correct.

Accepted Answer

When the coefficient of correlation $r = 0$, it indicates that there is no linear relationship between the variables, which means the slope of the regression line is zero (since the slope is influenced by $r$), and the coefficient of determination (which is $r^2$) is also zero, reflecting no explained variance in the dependent variable by the independent variable.

Question 7

The numerical value of the coefficient of determination r ² A) is the proportion of the variation in the dependent variable y that is explained by the best-fit linear equation. B) is the proportion of the variation in the independent variable x that is explained by the best-fit linear equation. C) indicates the direction of the relationship between the dependent variable y and the independent variable x. D) Both A and B are correct. E) A,B,and C are all correct.

Accepted Answer

The coefficient of determination, denoted by r-squared (r^2), is the proportion of the total variation in the dependent variable y that is explained by the best-fit linear equation. Therefore, option A is correct. Option B is incorrect because r-squared is not a measure of the variation in the independent variable x. Option C is also incorrect because the sign of the coefficient of determination does not indicate the direction of the relationship between x and y.

Question 8

Which of the following statements is not correct?
A) Measures of central tendency determined from frequency distributions will only be approximations of the actual values.
B) Measures of dispersion determined from frequency distributions will only be approximations of the actual values.
C) In grouped data,each observation is given the value of its classification's mid-point.
D) When data are grouped,the value of each individual observation is lost.
E) All of the above statements are correct.

Accepted Answer

All the statements provided are correct in the context of statistical analysis. Measures of central tendency and dispersion derived from frequency distributions are indeed approximations because they rely on grouped data rather than individual data points. In grouped data, each observation is assigned the value of its group's midpoint, which leads to the loss of specific individual data values, making all the statements accurate reflections of the limitations and characteristics of working with grouped data.

Question 9

When the standard deviation is expressed as a percentage of the mean,the result is the:
A) coefficient of correlation.
B) coefficient of determination.
C) coefficient of variation.
D) coefficient of dispersion.

Accepted Answer

The coefficient of variation is calculated as the standard deviation divided by the mean, multiplied by 100. This gives the standard deviation as a percentage of the mean, which is useful for comparing the variability of different data sets with different means.

Question 10

You are interested in beginning a small business enterprise and one aspect of your research is to look at the loan record for stockholders of small business corporations.A14-year record of net loans from stockholders of small business corporations (in billions of dollars)are as follows: 1.6,-0.2,1.0,1.4,-0.1,0.6,1.5,0.9,2.2,1.3,1.9,1.9,2.8,and 5.0.
Calculate the mode.
____________________ billion

Accepted Answer

The answer of You are interested in beginning a small...

Question 11

For each of the past 10 years,the U.S.unemployment rate has been recorded as follows: 6.7,5.5,5.7,5.2,4.5,3.8,3.8,3.6,3.5,and 4.9.Find the mean unemployment rate for this period.

Accepted Answer

The answer of For each of the past 10 years,the...

Question 12

You are interested in beginning a small business enterprise and one aspect of your research is to look at the loan record for stockholders of small business corporations.A14-year record of net loans from stockholders of small business corporations (in billions of dollars)are as follows: 1.6,-0.2,1.0,1.4,-0.1,0.6,1.5,0.9,2.2,1.3,1.9,1.9,2.8,and 5.0.
Calculate the median.
____________________ billion

Accepted Answer

The answer of You are interested in beginning a small...

Question 13

A student scores 89,72,93,and 84 on four exams during the semester and 96 on the final exam.If the final is weighted double and the four others weighted equally,what would the student's final average be?

Accepted Answer

The answer of A student scores 89,72,93,and 84 on four...

Question 14

The coefficient of correlation r is a number that indicates the:
A) direction of the relationship between the dependent variable y and the independent variable x.
B) strength of the relationship between the dependent variable y and the independent variable x.
C) proportion of the variation in the dependent variable y that is explained by the independent variable x.
D) Only A and B are correct.
E) A,B,and C are all correct.

Accepted Answer

The coefficient of correlation r indeed indicates both the direction (A) and the strength (B) of the relationship between two variables. However, it does not directly indicate the proportion of variation in the dependent variable explained by the independent variable; that is described by the coefficient of determination (r^2), not the coefficient of correlation r itself.

Question 15

A perfect straight line sloping upward would produce a correlation coefficient equal to:
A) +1.
B) -1.
C) +2.
D) -2.

Accepted Answer

A perfect straight line sloping upward indicates a perfect positive relationship between two variables. The correlation coefficient, which measures the strength and direction of a linear relationship, ranges from -1 to +1. A positive correlation coefficient of +1 indicates a perfect positive relationship, while a negative correlation coefficient of -1 indicates a perfect negative relationship. A perfect straight line sloping upwards would therefore produce a correlation coefficient of +1.

Question 16

You are interested in beginning a small business enterprise and one aspect of your research is to look at the loan record for stockholders of small business corporations.A14-year record of net loans from stockholders of small business corporations (in billions of dollars)are as follows: 1.6,-0.2,1.0,1.4,-0.1,0.6,1.5,0.9,2.2,1.3,1.9,1.9,2.8,and 5.0.
Calculate the mean.
____________________ billion

Accepted Answer

The answer of You are interested in beginning a small...

Question 17

A sample of 10 U.S.families spent the following amounts (in dollars)on groceries during a one-week period: 31.36,68.76,12.25,10.85,24.89,31.48,49.52,48.24,30.04,and 25.63.Find the median amount spent on groceries.

Accepted Answer

The answer of A sample of 10 U.S.families spent the...

Question 18

A sample of interest rates on unpaid credit card balances yields the following data: 13.25,13.67,13.60,13.29,12.97,12.90,12.76,12.66,12.58,12.77,and 12.91.Find the median interest rate.

Accepted Answer

The answer of A sample of interest rates on unpaid...

Question 19

Heidi has been keeping track of what she spends to eat out.The last week's expenditures (in dollars)for meals eaten out were 3.69,3.95,4.19,8.91,5.49,12.53,and 5.66.Calculate the mean amount she spent on meals last week.

Accepted Answer

The answer of Heidi has been keeping track of what...

Question 20

The difference between the mean of a data set and the individual values of that set is known as the:
A) variance
B) standard deviation
C) residual
D) mean absolute deviation
E) quartile

Accepted Answer

The difference between the mean of a data set and the individual values of that set is known as the residual. Variance and standard deviation measure the amount of spread or dispersion in a data set. Mean absolute deviation measures the average distance between each data point and the mean. Quartile is a measure of central tendency that divides a data set into four equal parts.

Quiz 3: Statistical Description of Data

Sample values of 13 monthly sales figures (in thousands of dollars)are: 6,5,6,6,7,8,9,10,10,10,9,9,and 6. What is the mean sales figure? ____________________ thousand

If the coefficient of correlation $r=\pm 1$ ,then the best-fit linear equation will include:

The average profit per unit for Product A is $5.32,Product B is $7.98,and Product C is $9.69.If the percentages of each sold are 36,29,and 35 respectively,what is the weighted mean profit per unit?

For a set of data,the mean is 50 and the standard deviation is 10.In the raw data,one of the observations is equal to 74.After the data are standardized,what will be the standardized value of this observation?

The length of the box in the box-and-whisker plot portrays the:

If the coefficient of correlation r = 0,then:

The numerical value of the coefficient of determination r ²

Which of the following statements is not correct?

When the standard deviation is expressed as a percentage of the mean,the result is the:

For each of the past 10 years,the U.S.unemployment rate has been recorded as follows: 6.7,5.5,5.7,5.2,4.5,3.8,3.8,3.6,3.5,and 4.9.Find the mean unemployment rate for this period.

A student scores 89,72,93,and 84 on four exams during the semester and 96 on the final exam.If the final is weighted double and the four others weighted equally,what would the student's final average be?

The coefficient of correlation r is a number that indicates the:

A perfect straight line sloping upward would produce a correlation coefficient equal to:

A sample of 10 U.S.families spent the following amounts (in dollars)on groceries during a one-week period: 31.36,68.76,12.25,10.85,24.89,31.48,49.52,48.24,30.04,and 25.63.Find the median amount spent on groceries.

A sample of interest rates on unpaid credit card balances yields the following data: 13.25,13.67,13.60,13.29,12.97,12.90,12.76,12.66,12.58,12.77,and 12.91.Find the median interest rate.

Heidi has been keeping track of what she spends to eat out.The last week's expenditures (in dollars)for meals eaten out were 3.69,3.95,4.19,8.91,5.49,12.53,and 5.66.Calculate the mean amount she spent on meals last week.

The difference between the mean of a data set and the individual values of that set is known as the:

Quiz 3: Statistical Description of Data

Sample values of 13 monthly sales figures (in thousands of dollars)are: 6,5,6,6,7,8,9,10,10,10,9,9,and 6. What is the mean sales figure? ____________________ thousand

If the coefficient of correlation r=±1 r=\pm 1 r=±1 ,then the best-fit linear equation will include:

The average profit per unit for Product A is $5.32,Product B is $7.98,and Product C is $9.69.If the percentages of each sold are 36,29,and 35 respectively,what is the weighted mean profit per unit?

For a set of data,the mean is 50 and the standard deviation is 10.In the raw data,one of the observations is equal to 74.After the data are standardized,what will be the standardized value of this observation?

The length of the box in the box-and-whisker plot portrays the:

If the coefficient of correlation r = 0,then:

The numerical value of the coefficient of determination r 2

Which of the following statements is not correct?

When the standard deviation is expressed as a percentage of the mean,the result is the:

For each of the past 10 years,the U.S.unemployment rate has been recorded as follows: 6.7,5.5,5.7,5.2,4.5,3.8,3.8,3.6,3.5,and 4.9.Find the mean unemployment rate for this period.

A student scores 89,72,93,and 84 on four exams during the semester and 96 on the final exam.If the final is weighted double and the four others weighted equally,what would the student's final average be?

The coefficient of correlation r is a number that indicates the:

A perfect straight line sloping upward would produce a correlation coefficient equal to:

A sample of 10 U.S.families spent the following amounts (in dollars)on groceries during a one-week period: 31.36,68.76,12.25,10.85,24.89,31.48,49.52,48.24,30.04,and 25.63.Find the median amount spent on groceries.

A sample of interest rates on unpaid credit card balances yields the following data: 13.25,13.67,13.60,13.29,12.97,12.90,12.76,12.66,12.58,12.77,and 12.91.Find the median interest rate.

Heidi has been keeping track of what she spends to eat out.The last week's expenditures (in dollars)for meals eaten out were 3.69,3.95,4.19,8.91,5.49,12.53,and 5.66.Calculate the mean amount she spent on meals last week.

The difference between the mean of a data set and the individual values of that set is known as the:

If the coefficient of correlation $r=\pm 1$ ,then the best-fit linear equation will include:

The numerical value of the coefficient of determination r ²