EXAM 1 CHAPTERS 1, 3,& 4
The ages of all the patients in the isolation ward of the hospital are 38, 26, 13, 41, and 22. What is the population variance?
106.8
The test scores for a class of 147 students are computed. What is the location of the test score associated with the third quartile?
111
Over the last six months, the following numbers of absences have been reported: 20, 4, 12, 18, 14, and 10. What is the median number of monthly absences?
13
The test scores for a class of 215 students are computed. What is the location of the test score associated with the third quartile?
162
Students in a statistics class answered a quiz question and the time it took each student to complete it was recorded. The results are summarized in the following frequency distribution. Length of Time (in minutes) Number 0 up to 2 3 2 up to 4 6 4 up to 6 20 6 up to 10 8 What is the standard deviation(in minutes)?
2
A sample of small bottles and their contents has the following weights (in grams): 4, 2, 5, 4, 5, 2, and 6. What is the sample variance of bottle weight?
2.33
In the following set of data: (1, 3, 5, 6, 7, 9, 100), what are the first, second, and third quartiles?
3, 6, and 9
Quartiles divide a distribution into ________________.
4 equal parts
In the following set of data: (2, 4, 5, 6, 7, 41, 100), what are the first, second, and third quartiles?
4, 6, and 41
What is the sample variance of the following numbers? 6, 4, 2, 7, 1
6.50
Over the last six months, the following numbers of absences have been reported: 6, 0, 10, 14, 8, and 0. What is the median number of monthly absences?
7
What is the sample variance of the following numbers? 2, 8, 3, 4, 1
7.30
Which of the following statements is true about the correlation coefficient?
A correlation coefficient of zero means that two quantitative variables are not linearly related to each other.
Which of the following is not an example of a statistic?
A list of the profits earned last year for 100 companies in the United States
What type of variable is "pounds of popcorn" served at a movie theater?
Continuous
A question in a market survey asks for a respondent's favorite car color. Which measure of central location should be used to summarize this question?
Mode
Which measures of central location are not affected by extremely small or extremely large values?
Mode and median
Which of the following is true?
No matter what your career, you need a knowledge of statistics to understand the world.
Respondents were asked, "Do you now earn more than or less than you did five years ago?" What is this level of measurement?
Nominal
Shoe style is an example of what level of measurement?
Nominal
A university wishes to conduct a student survey. In one of the questions, students are asked to mark their gender as either male or female. Gender is an example of the
Nominal Scale
If production determines sales, then a scatter diagram of these two variables is labeled with sales on the Y-axis and production on the X-axis.
True
Pearson's Coefficient of skewness is a measure of a distribution's symmetry.
True
Percentiles divide a distribution into 100 equal parts.
True
The correlation coefficient measures the strength and direction of the relationship between two quantitative variables.
True
For the past week, a company's common stock closed with the following prices: $61.5, $62, $61.25, $60.875, and $61.5. What was the price range?
$1.125
The monthly amounts spent for food by families of four receiving food stamps approximates a symmetrical, normal distribution. The sample mean is $150 and the standard deviation is $20. Using the Empirical rule, about 95% of the monthly food expenditures are between what two amounts?
$110 and $190
The sample variance of hourly wages was 10. What is the sample standard deviation?
$3.16
A sample of the paramedical fees charged by clinics revealed these amounts: $55, $49, $50, $45, $52, and $55. What is the median charge?
$51.00
The net incomes (in $millions) of a sample of steel fabricators are $86, $67, $86, and $85. What is the modal net income?
$86
A sample of experienced typists revealed that their mean typing speed is 87 words per minute and the median typing speed is 73 words per minute. The standard deviation of typing speed is 16.9 words per minute. What is the Pearson coefficient of skewness?
+2.5
What is the value of the Pearson's coefficient of skewness for a distribution with a mean of 45, a median of 26, and a standard deviation of 6?
+9.5
A large oil company is studying the number of gallons of gasoline purchased per customer at self-service pumps. The mean number of gallons is 10.0, with a standard deviation of 3.0 gallons. The median is 10.75 gallons. What is Pearson's coefficient of skewness in this instance?
-0.75
A large oil company is studying the number of gallons of gasoline purchased per customer at self-service pumps. The mean number of gallons is 14, with a standard deviation of 3 gallons. The median is 15 gallons. What is Pearson's coefficient of skewness in this instance?
-1.00
What is the possible range of values for Pearson's coefficient of skewness?
-3 and +3
For the most recent seven years, the U.S. Department of Education reported the following number of bachelor's degrees awarded in computer science: 12,029; 7,087; 6,866; 5,419; 11,989; 11,489; 13,233. What is the annual arithmetic mean number of degrees awarded?
About 9,730
A sample of assistant professors on the business faculty at state-supported institutions in Ohio revealed the mean income to be $72,000 for nine months, with a standard deviation of $3,000. Using Chebyshev's theorem, what proportion of the faculty earns more than $66,000, but less than $78,000?
At least 75%
When computing the arithmetic mean, the smallest value in the data set
Can be any value
A box plot graphically shows the 10th and 90th percentiles.
False
A correlation coefficient of +0.08 indicates strong positive correlation.
False
A student scored in the 85th percentile on a standardized test. This means that the student scored lower than 85% of all students who took the test.
False
The coefficient of skewness is the standard deviation divided by the mean.
False
What level of measurement is the Centigrade temperature scale?
Interval
What is a disadvantage of the range as a measure of dispersion?
It is based on only two observations
The sum of the deviations of each data value from this measure of central location will always be zero.
Mean
The net annual sales of a sample of small retail clothing stores were organized into the following relative frequency distribution. Net Sales ($ millions) Percent Total 1 up to 4 13 4 up to 7 14 7 up to 10 40 10 up to 13 23 13 or more 10 What is the mean net sales (in $ millions)?
Mean cannot be computed
The final rankings of the top 20 NCAA college basketball teams are an example of which level of measurement?
Ordinal
Which word is not part of the definition of descriptive statistics?
Predicting
The names of the positions in a corporation, such as chief operating officer or controller, are examples of what type of variable?
Qualitative
If the variance of the "number of daily parking tickets" issued is 100, the standard deviation is defined as the _____________.
Square root of the variance of the "number of daily parking tickets"
When statisticians analyze sample data in order to draw conclusions about the characteristics of a population, this is referred to as
Statistical inference.
What is the relationship between the variance and the standard deviation?
Variance is the square of the standard deviation
A correlation coefficient is calculated and found to be equal to −1.0. Which of the following statements is true?
The points in a scatter plot of the two variables will be in a straight line with a negative slope.
When TV advertisements report that "2 out of 3 dentists surveyed indicated they would recommend Brand X toothpaste to their patients," an informed consumer may question the conclusion because
the advertisement does not include the total number of dentists surveyed
A dot plot can be used to show _____________________.
the distribution for a quantitative variable
The 67th percentile is __________________.
The value below which 67% of the observations occur
A box plot graphically includes the 25th, 50th, and 75th percentiles.
True
A box plot shows the skewness of a distribution.
True
A correlation coefficient of -0.8 indicates strong indirect relationship.
True
A correlation coefficient of −0.8 indicates strong indirect relationship.
True
If a distribution is negatively skewed, the distribution is not symmetrical and the long tail is to the left.
True
A company wishes to know whether advertising expenditure is related to sales volume. Using the past two years of data for these two variables, they determined the correlation coefficient is +0.93. This indicates
a strong direct relationship between advertising expenditure and sales volume.
The diagram that is best at displaying data dispersion is a:
box plot
The interquartile range is graphically presented in a ___________.
box plot
The Inclusive Method
determines different locations for the first and third quartiles than the Exclusive Method.
A box plot graphically displays ____________.
the minimum, maximum, median, 25th percentile, and 75th percentile values
What statistics are needed to draw a box plot?
the minimum, maximum, median, first and third quartiles
What is the relationship among the mean, median, and mode in a symmetric distribution?
they are all equal
A disadvantage of using an arithmetic mean to summarize a set of data is that _________________.
it can be biased by one or two extremely small or large values
The length of a bridge, measured in meters, is an example of
quantitative data
When pharmaceutical companies try a new vaccine on a portion or part of a population, this is called a:
sample
The general process of gathering, organizing, summarizing, analyzing, and interpreting data is called
statistics
If Pearson's coefficient of skewness is equal to zero, the shape of the distribution is ________________.
symmetric
