Chapter 3 part 1

Question 1

Bimodal Distribution

Answer 1

Two Peaks. A data set is bimodal if it has two modes. This means that there is not a single data value that occurs with the highest frequency. Instead, there are two data values that tie for having the highest frequency.

Question 2

Correlation

Answer 2

The interdependence of variable quantities. It is used to test relationships between quantitative variables or categorical variables. In other words, it’s a measure of how things are related. The study of how variables are correlated is called correlation analysis.

Question 3

Correlation coefficient

Answer 3

Correlation coefficients are used in statistics to measure how strong a relationship is between two variables.

Question 4

Descriptive statistics

Answer 4

They are used to describe the basic features of the data in a study. They provide simple summaries about the sample and the measures. Together with simple graphics analysis, they form the basis of virtually every quantitative analysis of data.

Question 5

Frequency distribution

Answer 5

It is a representation, either in a graphical or tabular format, that displays the number of observations within a given interval. The interval size depends on the data being analyzed and the goals of the analyst. The intervals must be mutually exclusive and exhaustive. Frequency distributions are typically used within a statistical context. Generally, frequency distribution can be associated with the charting of a normal distribution.

Question 6

Interval scale of measurement

Answer 6

An interval scale is one where the order and the difference between two values is meaningful. Examples of interval variables include: temperature (Fahrenheit), temperature (Celsius), pH, SAT score (200-800), credit score (300-850).

Question 7

Mean

Answer 7

The Mean is the average. this is when you add all the number then divide the by the number of numbers.

Question 8

Measures of central tendency

Answer 8

It is a single value that attempts to describe a set of data by identifying the central position within that set of data. As such, measures of central tendency are sometimes called measures of central location.

Question 9

Median

Answer 9

The Median is the middle number of the sorted, ascending or descending, list of numbers and can be more descriptive

Question 10

Mode

Answer 10

Is the most number in the group. In other words, it repeated more often than any other.

Question 11

Multimodal distribution

Answer 11

Multimodal distribution is a probability distribution with two different modes, may also be referred to as a bimodal distribution. These appear as distinct peaks (local maxima) in the probability density function, as shown in Figures 1 and 2.

Question 12

Negative correlation

Answer 12

The slope of the graph is a down slope (negative). Negative correlation is a relationship between two variables in which one variable increases as the other decreases, and vice versa.

Question 13

Negatively skewed distribution

Answer 13

A negatively skewed (also known as left-skewed) distribution is a type of distribution in which more values are concentrated on the right side (tail) of the distribution graph while the left tail of the distribution graph is longer.

Question 14

Nominal scale of measurement

Answer 14

A Nominal Scale is a measurement scale, in which numbers serve as “tags” or “labels” only, to identify or classify an object. A nominal scale measurement normally deals only with non-numeric (quantitative) variables or where numbers have no value.

Question 15

Normal curve

Answer 15

A normal curve is a probability distribution curve of a normal random variable. In statistics, the area under the normal distribution curve and above the horizontal axis is the total of the all the probabilities of all observations.

Question 16

Normal distribution

Answer 16

(Bell curve) is the most important probability distribution in statistics because it fits many natural phenomena. For example, heights, blood pressure, measurement error, and IQ scores follow the normal distribution.

Question 17

Ordinal scale of measurement

Answer 17

This is the 2nd level of measurement that reports the ranking and ordering of the data without actually establishing the degree of variation between them. Ordinal level of measurement is the second of the four measurement scales. “Ordinal” indicates “order”. It can be named, grouped and also ranked.

Question 18

Positive correlation

Answer 18

Positive correlation is a relationship between two variables in which both variables move in tandem—that is, in the same direction. A positive correlation exists when one variable decreases as the other variable decreases, or one variable increases while the other increases.

Question 19

Positively skewed distribution

Answer 19

A positively skewed (or right-skewed) distribution is a type of distribution in which most values are clustered around the left tail of the distribution while the right tail of the distribution is longer.

Question 20

Range

Answer 20

Is when you take the larger number then subtract it with the smaller number.

Question 21

Ratio scale of measurement

Answer 21

This refers to the level of measurement in which the attributes composing variables are measured on specific numerical scores or values that have equal distances between attributes or points along the scale and are based on a “true zero” point.

Question 22

Skewed distribution

Answer 22

This is a normal curve and it is completely symmetrical, so there is no skew. The ends of the curve are called the tails of the distributions and if one of these tails was longer the distribution would be a skewed

Question 23

Standard deviation

Answer 23

This is a measure of how spread out numbers are. Its symbol is σ (the Greek letter sigma). The formula is easy: it is the square root of the …

Question 24

Variance

Answer 24

(σ2) in statistics is a measurement of the spread between numbers in a data set. That is, it measures how far each number in the set is from the mean and therefore from every other number in the set.

Question 25

Zero correlation

Answer 25

Correlation means association - more precisely it is a measure of the extent to which two variables are related. … A zero correlation exists when there is no relationship between two variables. For example their is no relationship between the amount of tea drunk and level of intelligence.