Question 1

Which of the following best describes the difference between descriptive and inferential statistics?

Accepted Answer

Descriptive statistics summarize or describe the data you have, while inferential statistics use sample data to make conclusions about a larger population.

Question 2

Suppose you want to know the average age of all students at a university. You randomly select 100 students and calculate their average age. In this scenario, which term describes the actual average age of all students at the university?

Accepted Answer

Parameter

Question 3

Which of the following sampling procedures involves dividing the population into groups and then randomly selecting some people from every group?

Accepted Answer

Stratified sampling

Question 4

A researcher observes how much time students spend studying without interfering or assigning any tasks. What type of research is this?

Accepted Answer

Observational research

Question 5

Which of the following is an example of a discrete variable?

Accepted Answer

Number of cars in a parking lot

Question 6

Which scale of measurement is used for the variable 'favorite color'?

Accepted Answer

Nominal

Question 7

A scale always reads 5 pounds heavier than your actual weight. What type of error is this?

Accepted Answer

Systematic error

Question 8

Refer to the first image (bar graph of pets). Which pet is the most popular in Class 2?

Accepted Answer

Dog

Question 9

Refer to the second image (pie chart). Which category represents the largest portion of the whole?

Accepted Answer

40%

Question 10

Refer to the third image (histogram of test scores). What does the tallest bar represent?

Accepted Answer

The score range with the most students

Question 11

Refer to the fourth image (stem-and-leaf plot). What is the smallest value in the data set?

Accepted Answer

12

Question 12

Refer to the fifth image (box-and-whisker plot diagram). What does the line inside the box represent?

Accepted Answer

The median

Question 13

Refer to the sixth image (boxplot of height). What does the IQR (interquartile range) represent?

Accepted Answer

The spread of the middle 50% of the data

Question 14

Given the data set: 2, 4, 6, 8, 10, what is the mean?

Accepted Answer

$$6$$

Question 15

How does an outlier affect the mean, median, and mode of a data set?

Accepted Answer

It strongly affects the mean, but usually not the median or mode.

Question 16

What is the formula for the variance of a population given data values $$x_1$$, $$x_2$$, ..., x_N$$ and mean $$\mu$$?

Accepted Answer

$$\$$\$$sigma^2$$ = \frac{1}{N} \sum_{i=1}^{N} (x_i - \$$mu)^2$$\$$ $$

Question 17

A student scores 90 on a test where the mean is 80 and the standard deviation is 5. What is the z-score for this student?

Accepted Answer

$$\z$$ = \frac{90 - 80}{5} = 2\$$ $$

Question 18

According to the Central Limit Theorem, what happens to the distribution of sample means as the sample size increases?

Accepted Answer

It becomes approximately normal, regardless of the population's distribution.

Question 19

If a population has mean $$\mu = 100$$ and standard deviation $$\sigma = 20$$, what is the standard error of the mean for samples of size $$n = 25$$?

Accepted Answer

$$\$$\sigma_x = \frac{20}{\sqrt{25}} = 4\$$ $$

Introductory Statistics Study Guide: Key Concepts and Data Analysis

Study Guide - Practice Questions

Study Guide - Flashcards