Statistics in Psychology

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Questions and Answers

What is the primary purpose of statistics in research?

To analyze, interpret, and make decisions based on data (correct)

To ensure all data is qualitative

To provide exact values for all data points

To eliminate variability in data sets

What type of variable is considered a cause in an experiment?

Independent variable (correct)

Dependent variable

Constant variable

Causal variable

Which of the following is true about discrete variables?

They have no meaningful description

They possess fractional values

They can take any value within a range

They have no intermediate values (correct)

In psychological statistics, what do dependent variables represent?

The outcome of interest Signup and view all the answers

Which type of variable can take any value within a given range?

Continuous variable Signup and view all the answers

What is the role of constants in research?

They remain the same throughout the study Signup and view all the answers

Which term best describes variables characterized by categories or groups?

Categorical variables Signup and view all the answers

Inferential statistics allow researchers to:

Make statements about larger populations based on small samples Signup and view all the answers

Which level of measurement includes values that are in order but do not have a consistent difference between them?

Ordinal Signup and view all the answers

Which assumption is NOT required for parametric statistics?

Descriptive Analysis Signup and view all the answers

What is a key characteristic of ratio level measurements?

Has an absolute zero Signup and view all the answers

In research designs, which method combines both quantitative and qualitative approaches?

Mixed Methods Signup and view all the answers

Which type of sample is more likely to provide external validity?

Probability Sample Signup and view all the answers

Which type of statistics would be appropriate if the scale fails to meet normal distribution criteria?

Nonparametric Statistics Signup and view all the answers

What type of analysis is primarily focused on numerical data?

Statistical Analysis Signup and view all the answers

Which level of measurement is characterized by possible values that are unordered?

Nominal Signup and view all the answers

What characteristic distinguishes an experimental research design from quasi-experimental design?

Random sampling and assignment Signup and view all the answers

Which sampling method is associated with a non-probability approach?

Snowball sampling Signup and view all the answers

When constructing a simple frequency table, what is usually contained in the two columns?

Possible scores and frequency Signup and view all the answers

Which graph type is most appropriate for displaying continuous data?

Histogram Signup and view all the answers

What is the lower real limit for a class interval of 60-64?

59.5 Signup and view all the answers

Which measure of central tendency is most affected by extreme values in a data set?

Mean Signup and view all the answers

What distinguishes a bimodal distribution from a normal distribution?

Presence of two peaks Signup and view all the answers

Which term describes a distribution where the mean is greater than the median?

Positively skewed Signup and view all the answers

In a grouped frequency distribution, what is typically grouped into equal-sized intervals?

Scores Signup and view all the answers

What does cumulative relative frequency represent?

The proportion of scores below a particular score Signup and view all the answers

Study Notes

Statistics

Statistics are a range of techniques for analyzing, interpreting, displaying, and making decisions based on data.
Descriptive statistics are used to describe a set of data.
Inferential statistics are used to make inferences about a larger population based on a smaller sample.
Psychological statistics are a collection of numerical facts about psychology.

Types of Variables

Independent variables are the cause.
Dependent variables are the outcome.
- Constants remain the same. - Discrete variables have no intermediate values, like the number of children in a family.
- Continuous variables can take any value within a given range, like height.
Categorical variables are characterized by categories or groups, like gender.

Scales/Levels of Measurement

Nominal: Possible values are unordered, for example, gender is nominal because there's no inherent order in male, female, or non-binary.
Ordinal: Values are ordered, and each value represents a greater or lesser magnitude than the others, but the intervals are not equal. For example, a student's ranking in a class would be ordinal data.
Interval: There is an arbitrary zero point, so differences between values are meaningful, but ratios are not. For example, a temperature scale (celsius or fahrenheit) is interval data because it has an arbitrary zero point. The difference between 10 degrees and 20 degrees is the same as the difference between 20 degrees and 30 degrees; however, 30 degrees is not twice as hot as 15 degrees.
Ratio: There is a true zero point, so both differences and ratios between values are meaningful, for example, height is ratio data.

Parametric vs Nonparametric Statistics

Parametric statistics are based on distributions and their parameters.
Assumptions of Parametric Statistics
- Normal Distribution
- Random Sampling
- Interval/Ratio Level of Measurement
- Homogeneity of Variance
Nonparametric statistics can be used when the scale of measurement does not meet the assumptions of parametric statistics.

Types of Research Design

Quantitative Research Design
- Numerical analysis, for example, a survey asking participants to rate their levels of happiness on a scale of 1 to 10.
Qualitative Research Design
- Descriptive Research
- Focuses on gathering non-numerical data, like, conducting interviews, observations, or analyzing text.
Mixed Methods Research Design
- Uses both quantitative and qualitative methods.
Population is the collection of people that could be measured.
Sample is a representative subset of the population.
A probability sample is more likely to represent the population than a nonprobability sample, which means it's more likely to have external validity.

Research Design

Experimental Research Design:
- Random Sampling
- Assignment
- Manipulation of IV
- This research design is used to determine causation.
Quasi-experimental Research Design:
- "Experiment-like"
- Not random sampling
- Manipulation of IV
Non-experimental Research Design:
Descriptive
Correlation
Regression
Comparative

Frequency Tables

Used to organize, describe, and interpret data in a more meaningful way.
They commonly arrange data from the highest to the lowest value.
Simple frequency tables are used for a large number of observations.
They are two-column tables that show possible scores and frequency.

Cumulative Frequency (Cf)

Calculated by adding up the frequencies from the lowest score to the current score.
Relative frequency tells us what proportion of the group attained each score.
Cumulative relative frequency shows the proportion of the scores that are at or below a given score.
Cumulative percent frequency shows the percentage of scores that are at or below a given score.

Graphing Results

Bar graph: Used for discrete and categorical data.
Histogram: Used for continuous data.
Line Graph: Used to visualize data over time.
Pie Chart: Used for no more than five categories and uses percentages.
Grouped frequency distribution: Used for grouping scores into equal-sized intervals (class intervals).

Measures of Central Tendency

Mean: Add all values together and divide by the number of values.
Median: The middle value in a distribution.
Mode: The most frequent value in a distribution.
Unimodal: One peak
Bimodal: Two peaks
Multimodal: More than two peaks
Positive Skewness: Floor effect (mean > median > mode)
Negative Skewness: Ceiling effect (mean < median < mode)

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Description

Explore the fundamental concepts of statistics used in psychology, including descriptive and inferential statistics. Understand different types of variables, such as independent and dependent variables, along with scales of measurement like nominal and ordinal. This quiz provides a comprehensive review for students studying psychological statistics.