Statistics Midterm Part 1

Except for rounding errors, relative frequencies should add up to what sum?

1

Approximately 68% of the data values will fall within how many standard deviations of the mean assuming it is empirical?

1.

How does one identify outliers?

1. Arrange the data in order to find Q1 and Q3 2. Find the IQR, which = Q3 - Q1 3. Multiply the IQR by 1.5 4. Subtract the value obtained in Step 3 from Q1 and add the value to Q3. 5. Check the data set for any data value that is smaller than Q1 - 1.5(IQR) or Q3 + 1.5(IQR).

What are the boundaries of the class 11-17?

10.5 and 17.5

In a pie graph, if pepperoni pizza were 24/72 of the distribution, how many degrees would be needed to represent pepperoni?

120°

What is the lower class limit in the class 13-17?

13

If two classes are 10 - 16 and 17 - 23, then the upper class boundary of 10 - 16 is

16.5

In an ungrouped frequency distribution of the average age of high school graduates, what would be the boundaries for the class of graduates who were reported to be 18 years old?

17.5 - 18.5 years old

Approximately 95% of the data values will fall within how many standard deviations of the mean assuming it is empirical?

2.

What are the limits of the class 3-19?

3 and 19

If a set of 25 numbers has standard deviation 8, then it's variance is

64, because variance = Deviation Squared.

Which of the following pairs of class limits would be appropriate for grouping the numbers 9, 12, 7, and 14 ?

7-10 and 11-14

An automobile dealer wants to construct a pie graph to represent types of cars sold in July. He sold 72 cars; 16 of which were convertibles. The convertibles will represent how many degrees in the circle?

80°

Which of the following correctly describes the relationship between a sample and a population?

A sample is a group of subjects selected from a population to be studied.

In a normal distribution (bell-shaped), what percent of data values fall within 3 standard deviations of the mean?

Approximately 99.7%

Thirty students recorded the colors of their eyes, choosing from the colors brown, blue, green, hazel, and black. This data can be appropriately summarized in a

Categorical frequency distribution

__________ consists of the collection, organization, summarization, and presentation of the data.

Descriptive statistics

A histogram is a graph that represents the cumulative frequencies for the classes in a frequency distribution.

False

Based on Mrs. Smith's electric bill for last year she expects that she will be paying $75/month this year. This is an example of descriptive statistics.

False

If a distribution is negatively skewed, the mean will fall to the right of the median and the mode will be on the left of the median.

False

In a research study, it is always preferable for the researcher to choose his participants as carefully as possible rather than randomly accept samples

False

The interquartile range or IQR is found by subtracting the mean from the maximum value of a data set.

False

In a chart, the height can be considered the independent variable and the age of the tree can be considered the dependent variable.

False, because the height is dependent on the age, which is independent.

______________ is a decision-making process for evaluating claims about a population, based on information obtained from samples.

Hypothesis testing

In an advertisement for a car, a driver is shown driving expertly through a difficult road course. At the bottom of the ad, the following is included in small print "Professional driver on a closed course". This is an example of

Implied connections

The two variables in a scatter plot are called the

Independent variable and dependent variable

If the value 6 has z score of -0.5 in a dataset, then the mean of that dataset is

It cannot be determined from the data given

The __________ is obtained by first adding the lower and upper limits and then dividing by 2.

Midrange

A __________ relationship exists when the points fall in a curved line.

Nonlinear

______________ are either extremely high or extremely low data values compared with the rest of the data.

Outliers

Which graph should be used to represent the frequencies with which certain courses are taken at Highlands Middle School?

Pareto chart

The number of people from the state of Alaska who voted for a Republican in the last election is an example of the ______________ level of measurement.

Ratio

A stem and leaf plot is useful for

Showing the distribution of costs of textbooks for various courses

The ______ retains the actual data while showing them in graphical form.

Stem and leaf plot

What does the five-number summary of a data set consist of?

The minimum, Q1, the median, Q3, and the maximum.

A pie graph is not useful to show which of the following characteristics of data?

The trend of the data over time

How do you find a data value corresponding to a given percentile?

Total number of values X Percentile / 100 If result is not a whole number, round to the next whole number. Starting at the lowest value, count over to the number that corresponds to the rounded-up value. If the result is a whole number, use the value halfway between the result and (result + 1)st values when counting up from the lowest value.

A dependent variable can also be referred to as an outcome variable

True

A pie graph was created showing the number of children per family. If 234 families were in the survey and the section depicting families with three children represented 120°, the number of families with three children was 78.

True

A time series graph represents data that occur over a specific time period

True

Chebyshev's theorem can be used to find the minimum percentage of data values that will fall between any two given values.

True

If every 13th customer leaving a movie were surveyed, this would be an example of systematic sampling

True

Inferential statistics is based on probability theory.

True

Methods commonly called traditional statistics include using measures of position, Chebyshev's theorem, and the coefficient of variation.

True

The frequency polygon and the histogram are two different ways to represent the same data set.

True

The lower class limit represents the smallest data value that can be included in the class.

True

The median can be a more appropriate measure of central tendency if the distribution of the data is extremely skewed

True

The unbiased estimator is included in the formula for calculating the variance of a sample because without it, the computed variance usually underestimates the population variance.

True

The variable of height is an example of a quantitative variable.

True

When running an experimental study, the group that is manipulated is called the treatment group

True

A scatter plot cannot be drawn when the dataset has

Two data points with missing x values

How does one find the Z-Score (Standard Score)?

Value - Mean / Standard deviation.

Greg wants to construct a frequency distribution for the political affiliation of the employees at Owen's Hardware Store. What type of distribution should he use?

categorical

The _________ is used for data that can be placed in nominal- or ordinal-level data.

categorical frequency distribution

Geographic locations are commonly studied in _____ samples

cluster

Statistics is the science of conducting studies to

collect, organize, summarize, analyze, and draw conclusions from data

The amount of time needed to run the Boston marathon is an example of which type of variable?

continuous

Oftentimes, implied connections do NOT use the word(s) ______ in their claims.

definitely

Which branch of statistics would buy a hundred Toyotas, drive them into the ground, record the final mileage, and then write a report for Car and Driver?

descriptive statistics

A magazine tests a new car and reports that it could be twice as fun to drive as it's predecessor. This is an example of

detached statistics

An advertisement for a lawn mower states that it is 10% more powerful than it's competitor. This is an example of

detached statistics

A ______________ variable assumes values that can be counted.

discrete

A pie graph is not useful in showing which of the following characteristics of a data set?

frequency changes over time

The three most commonly used graphs in research are the histogram, the __________, and the cumulative frequency graph (ogive).

frequency polygon

Which type of graph represents the data by using vertical bars of various heights to indicate frequencies?

histogram

Which branch of statistics would employ probability to predict how many miles one would be able to drive a 2000 Toyota Celica during its lifetime?

inferential statistics

If you classified the fruit in a basket as apple, orange, or banana, this would be an example of which level of measurement?

nominal

What level of measurement classifies data into mutually exclusive (nonoverlapping), exhaustive categories in which no order or ranking can be imposed on the data?

nominal

Rankings are normally placed in the _______ level of measurement.

ordinal

The _______________ level of measurement classifies data into categories that can be ranked; however, precise differences between the ranks do not exist.

ordinal

What is the term for a characteristic or measure obtained by using all the data values for a specific population?

parameter

A ______________ consists of all subjects that are being studied.

population

Is the following an example of a sample or population? If the answer is a sample, is the sample likely to be representative of the population. An administrator at the University runs a report to determine the average age of all students during the Fall semester.

population

The sex of a new-born baby in a local hospital is

qualitative

In a true experimental study, the subjects should be assigned to groups randomly. If this is not possible and a researcher uses intact groups, they are performing a

quasi-experimental study.

If a weather center monitors and calculates the average number of tornadoes that pass through Topeka, Kansas each year, what type of variable would they be investigating?

random variable

Variables with values that are determined by chance are called

random variables

What level of measurement possesses all the characteristics of interval measurement, and there exists a true zero?

ratio

What can be considered an advantage to experimental studies?

regulated variables

The graphs that have their distributions as proportions instead of raw data as frequencies are called

relative frequency graphs.

A time series graph is useful for which of the following purposes?

representing the changing frequencies of a data category over a period time

If you were told that four students from a class of twenty were questioned for a grade versus test preparation poll, this would be an example of

sampling

If data is clustered at one end or the other, it indicates that there is a __________.

skewed distribution

What type of sampling is being employed if the country is divided into economic classes and a sample is chosen from each class to be surveyed?

stratified sampling

The range 33.17 - 35.63 is not a good choice for class boundaries because

the class limits are difficult to interpret

A __________ graph would most appropriately represent the number of students that were enrolled in Statistics for each of the past ten years.

time series

A weatherman records the amount of rain that has fallen in Portland, Oregon during each day. What type of graph should he use?

time series graph

A ______ distribution is flat or rectangular.

uniform

Which of the following should not be done when constructing a frequency distribution?

use a class width with an even number

What is the term for a characteristic or attribute that can assume different values?

variable

The _______________and ______________ are used to determine the consistency of a variable.

variance, standard deviation