Data Types, Descriptive Statistics, and Basic Data Analysis Concepts

Which of the following describes categorical data

Can be either nominal or ordinal

In a perfectly symmetric distribution

Mean = Median = Mode

A researcher wants to test if average exam scores of one class differ from the national average. Which test applies

One-sample t-test

Which of the following best describes structured data

Data organized in rows and columns

Which of the following is a numerical variable

Temperature in Celsius

Temperature in Fahrenheit is measured on which scale

Interval

Which of the following is a floating-point number

3

In the same list, the value 10 is

Integer

Metadata refers to

Data about data

Which of the following is a difference between metadata and big data

Metadata is small and descriptive, big data is large and complex

The difference between data and information is mainly that

Information is organized and meaningful, while data is raw and unorganized

What is the main goal of data cleaning

To ensure the dataset is accurate and consistent

What is a common approach to handling outliers

Investigate context and decide whether to keep, remove, or transform

What is the best way to resolve inconsistent date formats

Convert all dates into a standard format

Which sampling method ensures every member of the population has an equal chance of being selected

Simple random sampling

Which measure of spread is most influenced by extreme values

Range

What does standard deviation measure

The average distance of data from the mean

Which is NOT a measure of central tendency

Standard deviation

If a distribution has a longer tail on the right, it is

Positively skewed

If the mean is greater than the median, the distribution is likely

Positively skewed

Which function calculates the standard deviation for a sample in Excel

STDEV.S()

Which Excel function can be used to measure skewness of a dataset

SKEW()

If SKEW(data) returns a positive value, what does this indicate

Data is positively skewed

The alternative hypothesis (Hₐ) represents

The claim we want to provide evidence for

Which correlation coefficient indicates the strongest relationship

r = −0.75

If X = temperature and Y = electricity use, a positive slope means

Higher temperatures are associated with higher electricity use

Categorical variables represent

Labels or groups without inherent numerical meaning

Nominal data is characterized by

Categories without a natural order

The main difference between interval and ratio data is

Interval data lacks a true zero point

Big data is typically characterized by the four Vs. Which is NOT one of them

Validity

Which of the following correctly represents the steps in the SOAR analytic model

Specify, Obtain, Analyze, Report

A pivot table is best described as

A statistical tool that reorganizes and summarizes data in a spreadsheet or database to create a report

Which of the following best describes data

Raw numbers and facts with little meaning on their own

When raw data are organized in a way that is meaningful to the user, they become

Information

In analytics, why is context important

It determines the setting in which data can be better understood and evaluated

Which is NOT a method to handle missing data

Visualization

Which Excel function is commonly used to remove extra spaces from text

TRIM()

Which of the following best defines a population in statistics

The entire set of individuals or items of interest

What is a sample

A subset of the population used to make inferences

Which of the following is a parameter

Population mean

Which of the following statements is true

Parameters describe populations; statistics describe samples

The mean is defined as

The sum of values divided by the number of observations

The mode is

The most frequently occurring value

Which dataset has a larger spread

Mean = 50, SD = 15

Which measure of central tendency is most affected by extreme values

Mean

Which of the following is most useful in identifying skewness

Comparison of mean and median

Which descriptive statistic is least reliable for skewed distributions

Mean

Which Excel function calculates the arithmetic mean of a dataset

AVERAGE()

Which function returns the middle value of an ordered dataset

MEDIAN()

Which function would you use to calculate the 25th percentile (Q1)

QUARTILE.EXC(array, 1)

What is the null hypothesis (H₀)

A statement of no effect or no difference

What does a p-value measure

Probability of observing results as extreme as the data if H₀ is true

If p-value < α, the correct conclusion is

Reject H₀

If p-value > α, then

Fail to reject H₀

Which of the following is a two-tailed test

H₀: μ = 50, Hₐ: μ ≠ 50

Which test compares a sample mean to a known population mean when σ is unknown

One-sample t-test

Which test compares means of two independent groups

Two-sample t-test

Which test checks differences in more than two group means

ANOVA

Which test is appropriate for paired data (before vs. after measurements)

Paired t-test

Which test examines whether two categorical variables are independent

Chi-square test of independence

A doctor measures patient weights before and after a new diet plan. Which test applies

Paired t-test

If r = 0, it means

No linear relationship exists between variables

A correlation coefficient of r = −0.25 suggests

Weak negative relationship

If two variables have r = 0.02, the relationship is

Almost no linear relationship

If all data points lie exactly on a straight line with positive slope, r =

1

High correlation between two variables means

A strong linear association exists

Which situation likely violates assumptions for correlation

Strong nonlinear relationship

The main purpose of linear regression is to

Predict the value of a dependent variable using one or more independent variables

In the simple linear regression equation Y = a + bX + ε, the term b represents

Slope

The intercept in a regression line represents

The expected value of Y when X = 0

The slope coefficient tells us

The change in Y for a one-unit increase in X

If the regression equation is Ŷ = 20 + 3X, then when X = 5, predicted Y is

35

If R² = 0.80, this means

80% of variation in Y is explained by X

A company predicts sales (Y) based on advertising spending (X). Which method should they use

Linear regression

A researcher finds slope = 0.75 for predicting GPA from study hours. This means

Each additional hour studied increases GPA by 0.75 units