EC0 201- Ch.1

Which of the following activities is an example of inferential statistics?

Performing a survey to record the earnings of a sample of NAU students and compiling summary statistics for the survey results to estimate values in the total NAU population.

What should you take into consideration when evaluating statistical claims? Check all that apply.

The statistics presented The sources of the statistical findings The procedures used to generate the claims

What should you take into consideration when evaluating statistical claims?

The statistics presented The sources of the statistical findings The procedures used to generate the claims

A grouped frequency distribution should be used instead of a frequency distribution when the

When a variable is truly continuous, each value will have a frequency of 1. Therefore, grouped frequency distributions are needed with continuous variables.

You hear in a commercial that 80% of children prefer to eat a certain kind of cereal for breakfast. What do you conclude?

You need to know more about the data

You want to find out if the gender of a student has any impact on the exam score. The gender of a student is

an independent variable a qualitative variable

Two basic divisions of statistics are

descriptive inferential

Uncertainty regarding conclusions about a population can be eliminated if you

obtain data from all members of the population.

There is debate about the value of computing means for

ordinal Data

A score on a 5-point quiz measuring knowledge of algebra is an example of a(n)

ordinal scale. *read section levels of measurement

In an experiment on the effect of sleep on memory, the dependent variable is

recall score on a memory test

Our data come from _______, but we really care most about ______.

samples; populations

The provost at NAU was interested in finding out whether students performed better in a traditional course or a blended-learning course. She commissioned a company to conduct a study. The company obtained the list of names from the Franke College of Business and use a random number generator to draw 80 students so that each had the sample chance to be selected. It then randomly assigned 40 students to a traditional course and the remaining to a blended-learning course. The students in these two courses make up a `

simple random sample sample with random assignment Sample

Higher rates of ice cream consumption and drowning for a city correspond. This leads people to believe that eating ice cream can somehow put you at risk of drowning. Is there another interpretation?

yes

A frequency distribution contains the frequency of every value in the distribution.

False -The distribution of empirical data is called a frequency distribution and consists of a count of the number of occurrences of each value.

A normal or bell-shaped distribution has its greatest probability density in its tails.

False-The distribution is higher and therefore denser in the middle of the distribution.

Which of the following are qualitative variables?

Gender Hair color

A symmetric distribution

In a symmetric distribution, the tails extend equally in both directions. Therefore, there is no skew

What is it called when one makes a decision concerning a population based on sample results?

Inferential statistics

Identify the scale of measurement for the following: heat measured in degrees centigrade.

Interval

Which of the following apply to a probability density?

It describes the probability of occurences of different values for a variable. It describes the probability of occurences of different values for a variable.

Which of the following apply to a frenquency distribution?

It is used to describe the distribution of discrete and categorical variables only. It describes the actual number of occurences of different values for a variable. *Section Distribution

City of birth is an example of a(n)

Nominal Scale

You design a questionnaire to collect data on "the ranking of a student in a class". What type of scale is this variable measured in?

Ordinal

You design a questionnaire to collect data on 'the class status of a student in terms "freshman", "sophomore", "junior", "senior"'. What type of scale is this variable measured in?

Ordinal

In an experiment on the effect of sleep on memory, the independent variable is

The number of hours of sleep

Identify the scale of measurement for the following: military title -- Lieutenant, Captain, Major.

The scale is ordinal. There is an inherent ordering in that a Major is higher than a Captain, which is higher than a Lieutenant.

Which of the following apply to a continuous distribution?

-It is used to describe the distribution of continuous variable only. -It describes the probability of occurences of different values for a variable.

You want to find out if the number of classes a student enrolls in a semester has any impact on the exam score. The number of classes a student enrolls in is

-an independent variable - quantitative variable

Which of the following are part(s) of statistics?

-interpretations and decisions based on the numbers and graphs -Graphs -numerical calculations

In a study of the effect of handedness on athletic ability, participants were divided into three groups: right-handed, left-handed, and ambidextrous. Athletic ability was measured on a 12-point scale. Check all that apply. The variable athletic ability is

-quantitative. -a dependent variable. -Discrete

For the scores 3, 5, 7, 9, 12, 21, 25, 30, calculate the 25th percentile based on "Definition 1."

According to Definition 1, the 25th percentile is the lowest score higher than 25% of the scores. Since there are 8 scores, this would be the lowest score higher than (0.25) x 8 = 2 scores. The score 7 is higher than the scores 3 and 5.

For the scores 3, 5, 7, 9, 12, 21, 25, 30, calculate the 25th percentile based on "Definition 2."

According to Definition 2, the 25th percentile is the lowest number greater than or equal to 25% of the scores. Since there are 8 scores, this would be the lowest number greater than or equal to (0.25) x 8 = 2 scores. The number 5 is greater than or equal to the scores 3 and 5.

A random sample

All FALSE 1. is more likely to be representative of the population than any other kind of sample. 2. is always representative of the population. 3. allows you to directly calculate the parameters of the population.

Which of the following activities is an example of descriptive statistics?

Computing the average and standard deviation of earnings for 25 randomly selected students on NAU campus.

Which of the following is inferential statistics?

Deal with drawing conclusions and/or making decisions concerning a population based only on sample data.

What is it called when one makes summary calculations on population or sample data?

Descriptive Data

Descriptive statistics

Descriptive statistics summarize and describe data. Inferential statistics use data from a sample to answer questions about a population. Inferential statistics involves generalizing beyond the data at hand.

You are interested in finding out what percentage of NAU students work at least 10 hours a week while going to school. You obtained the roster of a ECO 201 class from your professor, wrote down the names of students on pieces of paper, shuffled the pieces of paper in a hat and pull out 5 names. The set of all NAU students is a

Population

For the scores 3, 5, 7, 9, 12, 21, 25, 30, calculate the 25th percentile based on "Definition 3.

R = 25/100 x (8 + 1) = 2.25; IR = 2; FR = 0.25; The 25th percentile = 0.25 x (7-5) + 5 = 5.5.

When participants who arrive for a research study are put into treatment groups on the basis of chance,

Random Assignment has occurred

You design a questionnaire to collect data on "the average amount of sleep a student has everyday". What type of scale is this variable measured in?

Ratio

You design a questionnaire to collect data on "the weight of a student". What type of scale is this variable measured in?

Ratio

You design a questionnaire to collect data on "the average amount of sleep a student has everyday". What type of scale is this variable measured in?

Ratio *section levels of measurement

You are interested in finding out what percentage of NAU students work at least 10 hours a week while going to school. You obtained the roster of a ECO 201 class from your professor, wrote down the names of students on pieces of paper, shuffled the pieces of paper in a hat and pull out 5 names. The set of 5 names is a

Simple random Sample

Identify the scale of measurement for the following categorization of clothing: hat, shirt, shoes, pants

Since clothes are categorized and have no inherent order, the scale is nominal.

The area under the curve of a probability distribution is

The area is 1 by definition, meaning that the probability that a score chosen at random will occur under the curve is 1.

A random sample is one

in which every sample of a particular size has an equal probability of being selected.