Q: In a boxplot, which value is used to detect outliers?

$$Q_1 - 1.5$$ \times IQR$$ and Q_3$ + 1.5 \times IQR$$

Question 1

Refer to the Pareto chart of tropical cyclone wind speeds. Which wind speed category accounts for the highest frequency of cyclones, and what is the cumulative percentage at this point?

Accepted Answer

65 mph; cumulative percentage is about 40%

Question 2

Which of the following best describes the distribution shown in histogram B from the second image?

Accepted Answer

Symmetrical

Question 3

According to the Empirical Rule shown in the normal distribution diagram, what percentage of data falls within two standard deviations of the mean?

Accepted Answer

$$95\%$$

Question 4

In the boxplot diagram, what is the formula for the interquartile range (IQR)?

Accepted Answer

$$IQR = Q_3$ - Q_1$

Question 5

Given the probability distribution in Table 5-2, what is the expected value (mean) of the boredom tolerance test scores?

Accepted Answer

$$E(X) = \sum x P(x) = 2.72$$

Question 6

Which histogram shape from the second image (A-E) best matches the probability histogram for the boredom tolerance test scores?

Accepted Answer

B

Question 7

In hypothesis testing, which region in the left-tailed test diagram corresponds to the rejection region for the null hypothesis?

Accepted Answer

The left tail of the distribution

Question 8

If you are conducting a right-tailed hypothesis test, which alternative hypothesis are you testing?

Accepted Answer

$$H_1$$: \mu \u003e k$$

Question 9

In the two-tailed test diagram, what is the total area of the rejection regions if the significance level $$\alpha is$$ $$0.05$$?

Accepted Answer

$$0.025 in $$each tail, total $$0.05$$

Question 10

According to the decision flowchart, which test should you use if the population standard deviation $$\sigma is $$unknown and $$n \geq 30$$?

Accepted Answer

T-test

Question 11

A researcher wants to estimate the mean height of a population. The population is normally distributed, $$\sigma is $$known, and $$n = 50. $$Which formula should be used for the margin of error $$E$$ for a $$95\%$$ confidence interval?

Accepted Answer

$$E = z_c \cdot \dfrac{\sigma}{\sqrt{n}}$$

Question 12

Which of the following statements about the Empirical Rule is correct?

Accepted Answer

$$95\% of $$data falls within $$\mu \pm 2\sigma$$

Question 13

In a boxplot, which value is used to detect outliers?

Accepted Answer

$$Q_1 - 1.5$$ 	imes IQR$$ and Q_3$ + 1.5 	imes IQR$$

Question 14

Given a normal distribution with mean $$\mu$$ and standard deviation $$\sigma$$, what is the z-score for a value $$x$$?

Accepted Answer

$$z = \dfrac{x - \mu}{\sigma}$$

Question 15

Which of the following is NOT a property of the normal distribution?

Accepted Answer

The curve is skewed right

Comprehensive Study Notes for Introductory Statistics

Study Guide - Practice Questions

Study Guide - Flashcards