Question 1

Which of the following best describes the main purpose of statistics?

Accepted Answer

To collect, organize, summarize, analyze, and draw conclusions from data.

Question 2

A pharmaceutical company wants to test a new drug. They give the drug to one group and a placebo to another group, then compare the results. What type of study is this?

Accepted Answer

Experiment

Question 3

Which of the following is an example of quantitative data?

Accepted Answer

The heights of students in a classroom

Question 4

What is the formula for the midpoint of a class in a frequency distribution?

Accepted Answer

$$Midpoint = \frac{Lower\ limit + Upper\ class\ limit}{2}$$

Question 5

A frequency histogram must have which of the following properties?

Accepted Answer

Consecutive bars must touch

Question 6

Which formula correctly calculates the range of a data set?

Accepted Answer

$$Range = Maximum\ data\ entry - Minimum\ data\ entry$$

Question 7

Which of the following best describes a cumulative frequency graph (ogive)?

Accepted Answer

A line graph that displays cumulative frequencies at upper class boundaries

Question 8

Given the following data set: 2, 4, 6, 8, 10. What is the population mean?

Accepted Answer

$$\mu = \frac{2+4+6+8+10}{5} = 6$$

Question 9

A weighted mean is used when:

Accepted Answer

Entries in the data set have varying importance or frequency

Question 10

What is the formula for the population variance of a data set with $$N$$ entries?

Accepted Answer

$$\$$sigma^2$$ = \frac{\sum (x - \mu)^2$}{N}$$

Question 11

According to the Empirical Rule (68-95-99.7 Rule), approximately what percentage of data falls within two standard deviations of the mean in a bell-shaped distribution?

Accepted Answer

95%

Question 12

A probability experiment consists of flipping a coin and rolling a six-sided die. How many outcomes are in the sample space?

Accepted Answer

12

Question 13

Which of the following is NOT a step in constructing a frequency distribution?

Accepted Answer

Calculating the mean of the data set

Question 14

In a survey, which of the following is a potential source of bias?

Accepted Answer

Allowing respondents to self-select into the sample

Question 15

If the standard deviation of a population is $$\sigma = 5$$, what is the population variance?

Accepted Answer

$$\$$sigma^2$$ = 25$$

Question 16

Which of the following best describes an observational study?

Accepted Answer

A researcher observes and measures characteristics but does not change existing conditions.

Question 17

What is the formula for relative frequency?

Accepted Answer

$$Relative\ frequency = \frac{f}{n}$$

Question 18

A cumulative frequency for a class is:

Accepted Answer

The sum of the frequencies of that class and all previous classes

Question 19

Which of the following is a correct property of a frequency histogram?

Accepted Answer

The horizontal scale is quantitative and measures the data entries.

Question 20

If a data set has a mean of 50 and a standard deviation of 5, what is the range of values that contains approximately 68% of the data according to the Empirical Rule?

Accepted Answer

45 to 55

Introductory Statistics: Core Concepts and Methods

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