Statistics Technology & Digital Applications 3

Question 1

A data scientist uses Python's pandas library and calls df.describe(). Which statistic is NOT included in the default output?

Accepted Answer

Mode

Answer

df.describe() includes count, mean, std, min, 25th/50th/75th percentiles, and max — but not mode.

Question 2

When using SPSS to run an independent samples t-test, Levene's Test is automatically reported. What null hypothesis does Levene's Test evaluate?

Accepted Answer

The group variances are equal

Answer

Levene's Test checks the assumption of homogeneity of variance (equal variances) between groups before interpreting t-test results.

Question 3

In R's ggplot2 package, which function adds a linear regression line to a scatter plot?

Accepted Answer

geom_smooth(method='lm')

Answer

geom_smooth(method='lm') fits and plots a linear model trend line with optional confidence interval shading.

Question 4

A statistician stores a large dataset in a PostgreSQL database and needs only distinct values of a categorical column 'region'. Which SQL clause achieves this?

Accepted Answer

SELECT DISTINCT region

Answer

SELECT DISTINCT eliminates duplicate values and returns each unique value in the specified column exactly once.

Question 5

Which Python library provides the chi-square test of independence via the function scipy.stats.chi2_contingency()?

Accepted Answer

SciPy

Answer

SciPy's stats module contains chi2_contingency(), which computes the chi-square statistic, p-value, degrees of freedom, and expected frequencies.

Statistics Practice Test

Statistics Practice Test

Statistics Technology & Digital Applications 3