Q: If you want to check for outliers in a data set, which rule would you use?

Values less than $$Q_1 - 1.5$$ \times IQR$$ or greater than Q_3$ + 1.5 \times IQR$$

Question 1

Which of the following best describes the difference between a parameter and a statistic?

Accepted Answer

A parameter is a numerical summary of a population, while a statistic is a numerical summary of a sample.

Question 2

Suppose you are conducting a study on the heights of all students at your university. Which of the following is a qualitative variable?

Accepted Answer

Gender of the student

Question 3

Which sampling method is most likely to introduce bias if you only select students who are present in the library at noon?

Accepted Answer

Convenience sampling

Question 4

A researcher wants to compare the effectiveness of two medications. She randomly assigns patients to receive either medication A or medication B and measures their recovery times. What type of study is this?

Accepted Answer

Experiment

Question 5

Given the following data set: 2, 4, 6, 8, 10. What is the sample mean? Use the formula $$\bar{x} = \frac{\sum x_i}{n}.$$

Accepted Answer

$$\bar{x} = 6$$

Question 6

Which measure of center is most appropriate for describing the typical value in a highly skewed distribution?

Accepted Answer

Median

Question 7

If the largest value in a data set is 25 and the smallest value is 5, what is the range?

Accepted Answer

$$	ext{Range} = 20$$

Question 8

A sample of exam scores has a mean of 70 and a standard deviation of 10. According to the Empirical Rule, approximately what percentage of scores fall between 60 and 80?

Accepted Answer

About 68%

Question 9

Which formula would you use to calculate the sample standard deviation for ungrouped data?

Accepted Answer

$$s = \sqrt{\frac{\sum (x_i - \bar{x})^2$}{n-1}}$$

Question 10

A student scored 85 on a test where the mean was 75 and the standard deviation was 5. What is the student's z-score? Use $$z = \frac{x - \bar{x}}{s}.$$

Accepted Answer

$$z = 2$$

Question 11

Which of the following best describes a histogram?

Accepted Answer

A graph that displays frequencies for quantitative data using adjacent bars

Question 12

Which measure is NOT resistant to outliers?

Accepted Answer

Mean

Question 13

If a data set has a five-number summary of 10, 20, 30, 40, 50, what is the interquartile range (IQR)?

Accepted Answer

$$	ext{IQR} = 20$$

Question 14

Which of the following is a correct step in finding the median of a data set?

Accepted Answer

Arrange the data in ascending order

Question 15

A boxplot is most useful for displaying which of the following?

Accepted Answer

The five-number summary and potential outliers

Question 16

Which of the following is a quantitative variable?

Accepted Answer

Number of books read in a year

Question 17

If you want to check for outliers in a data set, which rule would you use?

Accepted Answer

Values less than $$Q_1 - 1.5$$ 	imes IQR$$ or greater than Q_3$ + 1.5 	imes IQR$$

Question 18

Which of the following best describes the purpose of stratified sampling?

Accepted Answer

To divide the population into groups and sample from each group to ensure representation

Question 19

Which graph is best for displaying the distribution of a categorical variable?

Accepted Answer

Bar graph

Question 20

A researcher collects data on the number of hours students study per week and their exam scores. Which type of graph would best display the relationship between these two variables?

Accepted Answer

Scatterplot

Statistics Unit 1 (Chapters 1-3) Study Guide: Data Collection, Summarizing, and Numerical Description

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