Stats test 1

midpoint

(upper class limit + lower limit) /2

how to find lower and upper class boundary

- Subtract the upper class limit for the first class from the lower class limit for the second class. - Divide the result by two. - Subtract the result from the lower class limit and add the result to the the upper class limit for each class.

2,9,12,3,12,13,8,5 Calculate the value of the range.

11

σ

= standard deviation

IQ scores, reported in whole numbers, of research scientists are an example of which type of data?

discrete

Months of the year are an example of which type of data?

qualitative

Which choice best describes the ordinal level of measurement?

this level of measurement consists of data values that are able to be arranged in a meaningful order, but are still considered to be of the qualitative or categorical type.

Which choice best describes the interval level of measurement?

this level of measurement consists of data values that can be subtracted from each other to tell what their difference means in the context of data values, but in this level, a value of zero does not mean that we have none of the item being measured. this data level is considered to be of the quantitative or numerical type.

Consider the following data. 5,−2,−5,−8,−6,5,−2,55,−2,−5,−8,−6,5,−2,5 Determine the mean of the given data.

-1

Consider the following data. 5,−2,−5,−8,−6,5,−2,5 Determine the median of the given data.

-2

Calculate the standard score of the given x value, x=27.3, where μ=25.3, σ=3.2. Round your answer to two decimal places.

.63

Calculate the GPA of a student with the following grades: C (10 hours), B (4 hours), F (21 hours). Note that an A is equivalent to 4.0, a B is equivalent to a 3.0, a C is equivalent to a 2.0, a D is equivalent to a 1.0, and an F is equivalent to a 0. Round your answer to two decimal places.

.91

Consider the following data: 2,9,12,3,12,13,8,5 Calculate the value of the sample variance. Round your answer to one decimal place.

18.3

Consider the following data: 2,9,12,3,12,13,8,5 Calculate the value of the sample standard deviation. Round your answer to one decimal place.

4.3

Consider the following data. 3,14,6,6,6,14,14 Determine the median of the given data.

6

A data set is bell shaped with mean 25 and standard deviation 6. What percent of the data values should be between 19 and 31?

68%

Consider the following data. 3,14,6,6,6,14,14 Determine the mean of the given data.

9

A data set is bell shaped with mean 25 and standard deviation 6. What percent of the data values should be between 7 and 43?

99.7%

class width

To find the width: Calculate the range of the entire data set by subtracting the lowest point from the highest, Divide it by the number of classes. Round this number up (usually, to the nearest whole number).

What is meant by the term "relative frequency" and how do we calculate it?

a class' relative frequency is the fraction or percentage of the data set that falls into that class, and is given by N, which equals the number of items in that class, divided by the total number of items in the data set.

Consider the following data. 3,14,6,6,6,14,14 Determine if the data set is unimodal, bimodal, multimodal, or has no mode. Identify the mode(s), if any exist.

bimodal = 14, 6

Three potential employees took an aptitude test. Each person took a different version of the test. The scores are reported below. Brittany got a score of 80.3; this version has a mean of 65.6 and a standard deviation of 7. Tera got a score of 240; this version has a mean of 201 and a standard deviation of 30. Tobias got a score of 7.8; this version has a mean of 7.4 and a standard deviation of 0.8. If the company has only one position to fill and prefers to fill it with the applicant who performed best on the aptitude test, which of the applicants should be offered the job?

brittany

Determine which term about frequency distributions best fits the description given. What do we call the value that separates one class from another (often found by averaging the upper limit of one class with the lower limit of the following class)?

class boundary

Determine which term about frequency distributions best fits the description given. What do we call the value that we get by averaging the lower and upper class limits based on the a single class?

class midpoint

Determine which term about frequency distributions best fits the description given. What do we call the value we get when we subtract the lower class limit describing one class from the lower class limit describing the following class?

class width

Decide which type of sampling technique fits the description given The population is subdivided into smaller groupings, each of which is similar to the population, and then some of the subgroups are tested, using every item from those subgroups to form the sample

cluster sampling

A statistics student interviews the last ten students to leave.

convenience sampling

Decide which type of sampling technique fits the description given Items are chosen in the easiest way possible for the researcher to gather data, which could easily lead to the sample not being very representative of the population

convenience sampling

weighted mean

create a t-chart (weight and data values) and multiply values across. add them together and then divide by your weight.

Which choice best describes the ratio level of measurement?

data values can be compared using fractions to say that one data value makes sense as a fraction of another. also a zero value means that there is none of the item being measured. and this data level is considered to be of the quantitative or numerical type.

Emperical Rule

first standard deviation = µ - σ to µ + σ (68% data) second standard deviation = µ - 2σ to µ + 2σ (95% data) third standard deviation = µ - 3σ to µ + 3σ (99% data)

Suppose we have quantitative (numerical) data that has already been arranged in a frequency distribution. Which way of presenting the data is most appropriate?

histogram

µ

mean

When asked to give a five-number summary for a data set, what values should be given, and in what order?

min, Q1, median, Q3, max

What term do statisticians give to a numerical value when it describes a characteristic of a population?

parameter

Suppose we have categorical (qualitative) data at the nominal level, and we wish to display how the size of each category differs from the other categories, particularly highlighting the largest and smallest categories. Which way of presenting the data is most appropriate?

pareto chart

Suppose we have qualitative (categorical) data that is at the nominal level, and the items being recorded can only fit into a single category option. If we wish to show how each category appears in relation to the total of all category frequencies, which way of presenting the data is most appropriate?

pie chart

What term do statisticians give to the complete collection of all items of interest in a statistical study?

population

Identify the population being studied and the sample chosen. The number of times 5 out of 40 students on your floor order fast food in a week.

population: the 40 students on your floor sample: 5 students selected on your floor

Classify the following data. Indicate whether the data is qualitative or quantitative, indicate whether the data is discrete, continuous, or neither, and indicate the level of measurement for the data. The temperature in Fahrenheit of a U.S. city each day for a month.

quantitative, continuous, interval

Decide which type of sampling technique fits the description given Items are chosen completely without bias or predetermination, so each item in the population has the same chance of being selected as any other item.

random sample

Determine whether the statement describes a population or a sample. The number of times 44 out of 3737 students on your floor order take-out in a week.

sample

What term do statisticians give to the subcollection of items that get tested to provide data in a statistical study?

sample

A survey of 3403 people in the U.S. revealed that 53% of those surveyed have debt.

sample statistic

A pollster interviews fifty voters from a district by randomly selecting the addresses with a random number generator.

simple random sampling

What term do statisticians give to a numerical value when it describes a characteristic of a sample?

statistic

Suppose we have numerical (quantitative) data that has not been grouped into classes, but is easy to classify based on the beginning and ending structure of the numbers for each data value. Which way of presenting the data is most appropriate?

stem and leaf plot

Decide which type of sampling technique fits the description given The population is subdivided into various groupings based on shared characteristics (such as gender or age bracket), and then every subgroup is sampled separately to collect data

stratified sampling

Decide which type of sampling technique fits the description given Items are chosen using a specified pattern, such as every 10th item from the population

systematic sampling

Identify the sampling technique used for the following study. A pollster interviews every tenth member from the entire population.

systematic sampling

Choose the best explanation for each level of measurement given Which choice best describes the nominal level of measurement?

this level of measurement consists o data values that are essential labels or names. data values at this level are considered to be qualitative or categorical type.

Consider the following data. 5,−2,−5,−8,−6,5,−2,5 Determine if the data set is unimodal, bimodal, multimodal, or has no mode. Identify the mode(s), if any exist.

unimodal = 5