Question 1

Expressed in percentiles, the interquartile range is the difference between the:

Accepted Answer

A)  20% and 80% values 
B)  45% and 95% values 
C)  25% and 75% values 
D)  20% and 70% values 
E)  10% and 90% values 
A)  20% and 80% values 
B)  45% and 95% values 
C)  25% and 75% values 
D)  20% and 70% values 
E)  10% and 90% values

Question 2

For any distribution, the standard deviation is a measure of variability of the data around the median.

Accepted Answer

A) True 
 B)False

Question 3

Attendance at London Symphony concerts for the past two years showed an average of 3,000 people per performance with a standard deviation of 100 people per performance. Attendance at a randomly selected concert was found to be 3,290. If attendance data is mound-shaped, does the attendance at the selected concert appear to be unusual?
__________
Justify your conclusion.
________________________________________________________

Accepted Answer

Yes; The z-score associated with 3,290 i

Question 4

In a histogram, the proportion of the total area which must be to the left of the median is:

Accepted Answer

A)  exactly 0.50 
B)  less than 0.50 if the distribution is skewed to the left 
C)  more than 0.50 if the distribution is skewed to the right 
D)  between 0.25 and 0.75 if the distribution is symmetric 
E)  all of these 
A)  exactly 0.50 
B)  less than 0.50 if the distribution is skewed to the left 
C)  more than 0.50 if the distribution is skewed to the right 
D)  between 0.25 and 0.75 if the distribution is symmetric 
E)  all of these

Question 5

In a psychological experiment, the time on task was recorded for ten subjects under a 5-minute time constraint. These measurements are in seconds:
182 197 207 272 192 257 247 197 232 237
a. Find the average time on task.
______________
b. Find the median time on task.
______________
c. If you were writing a report to describe these data, which measure of central tendency would you use?
______________
Explain.
________________________________________________________

Accepted Answer

222; 219.5; Mean; Since there

Question 6

Which of the following statements is true for the following data values: 17, 15, 16, 14, 17, 18, and 22?

Accepted Answer

A)  The mean, median and mode are all equal. 
B)  Only the mean and median are equal. 
C)  Only the mean and mode are equal. 
D)  Only the median and mode are equal. 
E)  The median and mode are not equal. 
A)  The mean, median and mode are all equal. 
B)  Only the mean and median are equal. 
C)  Only the mean and mode are equal. 
D)  Only the median and mode are equal. 
E)  The median and mode are not equal.

Question 7

A sample of students who have taken a calculus test has a mean score of 78.2, a mode of 67, and a median score of 67. Based on this information, the distribution of test scores is:

Accepted Answer

A)  symmetric 
B)  right skewed 
C)  left skewed 
D)  bimodal 
E)  none of these 
A)  symmetric 
B)  right skewed 
C)  left skewed 
D)  bimodal 
E)  none of these

Question 8

A sample of 25 observations has a standard deviation of 4. The sum of the squared deviations from the sample mean is:

Accepted Answer

A)  21 
B)  25 
C)  100 
D)  384 
E)  400 
A)  21 
B)  25 
C)  100 
D)  384 
E)  400

Question 9

If the 18th and 19th observations in a set of 25 data values are 42.6 and 43.8, then the 70th percentile value is:
______________

Accepted Answer

The answer of If the 18th and 19th observations in...

Question 10

Tchebysheff's Theorem states that: Given a number k greater than or equal to 1, and a set of measurements, at least (   ) of the measurements in the data set will lie within k standard deviations of their mean.

Accepted Answer

A) True 
 B)False

Question 11

The following data represent the scores for a sample of 10 students on a 20-point chemistry quiz:
16 14 2 8 12 12 9 10 15 13
Calculate the z score for the smallest and largest observations.
Smallest: ______________
Largest: ______________
Is either of these observations unusually large or unusually small?
______________

Accepted Answer

The answer of The following data represent the scores for...

Question 12

The 10th percentile of a set of measurements is the value which exceeds 90% of the measurements and is less than the remaining 10% of the measurements.

Accepted Answer

A) True 
 B)False

Question 13

One of the advantages of the standard deviation over the variance as a measure of variability is that the standard deviation is measured in the original units.

Accepted Answer

A) True 
 B)False

Question 14

Since the population is always larger than the sample, the population mean:

Accepted Answer

A)  is always larger than the sample mean 
B)  is always smaller than the sample mean 
C)  is always larger than or equal to the sample mean 
D)  can be smaller than, or larger than, or equal to the sample mean 
E)  is always smaller than or equal to the sample mean 
A)  is always larger than the sample mean 
B)  is always smaller than the sample mean 
C)  is always larger than or equal to the sample mean 
D)  can be smaller than, or larger than, or equal to the sample mean 
E)  is always smaller than or equal to the sample mean

Question 15

Which of the following measures is not affected by extreme values in the data?

Accepted Answer

A)  the mean 
B)  the median 
C)  the variance 
D)  the range 
E)  the standard deviation 
A)  the mean 
B)  the median 
C)  the variance 
D)  the range 
E)  the standard deviation

Question 16

Measures of variability are numbers that indicate the spread or scatter of observations; they show the extent to which individual values in a data set differs from one another and, hence, differ from their central location.

Accepted Answer

A) True 
 B)False

Question 17

Consider the data set: 5, 6, 7, 11, and 15. Its mean equals:

Accepted Answer

A)  7.0 
B)  8.8 
C)  8.1 
D)  7.3 
E)  9 
A)  7.0 
B)  8.8 
C)  8.1 
D)  7.3 
E)  9

Question 18

The sample variance calculated with a divisor of n gives a better estimate of the population variance,   , than does the sample variance,   , with a divisor of n - 1.

Accepted Answer

A) True 
 B)False

Question 19

The mean and variance of a sample of n = 25 measurements are 80 and 100, respectively. Explain in detail how to use Tchebysheff's Theorem to describe the distribution of measurements.

Accepted Answer

The distribution of measurements is cent

Question 20

Given the following frequency table:   
a. What fraction of the x values fall within two standard deviations of the mean?
______________
Within three standard deviations of the mean?
______________
b. Do the results of part (a) agree with Tchebysheff 's Theorem?
______________
c. Do the results of part (a) agree with the Empirical Rule?
______________

Accepted Answer

0.95; 0.96

Expressed in percentiles, the interquartile range is the difference between the:

For any distribution, the standard deviation is a measure of variability of the data around the median.

In a histogram, the proportion of the total area which must be to the left of the median is:

Which of the following statements is true for the following data values: 17, 15, 16, 14, 17, 18, and 22?

A sample of students who have taken a calculus test has a mean score of 78.2, a mode of 67, and a median score of 67. Based on this information, the distribution of test scores is:

A sample of 25 observations has a standard deviation of 4. The sum of the squared deviations from the sample mean is:

If the 18th and 19th observations in a set of 25 data values are 42.6 and 43.8, then the 70th percentile value is: ______________

Tchebysheff's Theorem states that: Given a number k greater than or equal to 1, and a set of measurements, at least ( ) of the measurements in the data set will lie within k standard deviations of their mean.

The following data represent the scores for a sample of 10 students on a 20-point chemistry quiz: 16 14 2 8 12 12 9 10 15 13 Calculate the z score for the smallest and largest observations. Smallest: Largest: Is either of these observations unusually large or unusually small? __

The 10^th percentile of a set of measurements is the value which exceeds 90% of the measurements and is less than the remaining 10% of the measurements.

One of the advantages of the standard deviation over the variance as a measure of variability is that the standard deviation is measured in the original units.

Since the population is always larger than the sample, the population mean:

Which of the following measures is not affected by extreme values in the data?

Measures of variability are numbers that indicate the spread or scatter of observations; they show the extent to which individual values in a data set differs from one another and, hence, differ from their central location.

Consider the data set: 5, 6, 7, 11, and 15. Its mean equals:

The sample variance calculated with a divisor of n gives a better estimate of the population variance, , than does the sample variance, , with a divisor of n - 1.

The mean and variance of a sample of n = 25 measurements are 80 and 100, respectively. Explain in detail how to use Tchebysheff's Theorem to describe the distribution of measurements.

Describing Data With Graphs

Describing Bivariate Data

Probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Estimation

Large-Sample Tests of Hypotheses

Inference From Small Samples

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters

Exam 2: Describing Data With Numerical Measures

Expressed in percentiles, the interquartile range is the difference between the:

For any distribution, the standard deviation is a measure of variability of the data around the median.

In a histogram, the proportion of the total area which must be to the left of the median is:

Which of the following statements is true for the following data values: 17, 15, 16, 14, 17, 18, and 22?

A sample of students who have taken a calculus test has a mean score of 78.2, a mode of 67, and a median score of 67. Based on this information, the distribution of test scores is:

A sample of 25 observations has a standard deviation of 4. The sum of the squared deviations from the sample mean is:

If the 18th and 19th observations in a set of 25 data values are 42.6 and 43.8, then the 70th percentile value is: ______________

Tchebysheff's Theorem states that: Given a number k greater than or equal to 1, and a set of measurements, at least ( ) of the measurements in the data set will lie within k standard deviations of their mean.

The 10th percentile of a set of measurements is the value which exceeds 90% of the measurements and is less than the remaining 10% of the measurements.

One of the advantages of the standard deviation over the variance as a measure of variability is that the standard deviation is measured in the original units.

Since the population is always larger than the sample, the population mean:

Which of the following measures is not affected by extreme values in the data?

Measures of variability are numbers that indicate the spread or scatter of observations; they show the extent to which individual values in a data set differs from one another and, hence, differ from their central location.

Consider the data set: 5, 6, 7, 11, and 15. Its mean equals:

The sample variance calculated with a divisor of n gives a better estimate of the population variance, , than does the sample variance, , with a divisor of n - 1.

The mean and variance of a sample of n = 25 measurements are 80 and 100, respectively. Explain in detail how to use Tchebysheff's Theorem to describe the distribution of measurements.

Describing Data With Graphs

Describing Bivariate Data

Probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Estimation

Large-Sample Tests of Hypotheses

Inference From Small Samples

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters

The 10^th percentile of a set of measurements is the value which exceeds 90% of the measurements and is less than the remaining 10% of the measurements.