Q: A student scores 1.5 standard deviations above the mean on a standardized test. If the mean is 100 and the standard deviation is 20, what is the student's score?

$$100 + (1.5 \times 20) = 130$$

Question 1

A pharmaceutical company wants to estimate the average recovery time for patients using a new drug. They randomly select 100 patients from a hospital and calculate the average recovery time. Which of the following best describes the average recovery time calculated from these 100 patients?

Accepted Answer

It is a statistic because it is calculated from a sample.

Question 2

Which of the following best describes the process of statistics?

Accepted Answer

Collecting data, organizing data, analyzing data, and interpreting results.

Question 3

A researcher records the number of cars passing through an intersection each hour. What type of variable is 'number of cars'?

Accepted Answer

Quantitative, discrete

Question 4

Which sampling method ensures that every member of the population has an equal chance of being selected?

Accepted Answer

Simple random sampling

Question 5

A teacher wants to display the distribution of test scores for her class. Which graphical method is most appropriate for showing the frequency of scores grouped into intervals?

Accepted Answer

Histogram

Question 6

Given the following data set: 2, 4, 4, 6, 8. What is the mode?

Accepted Answer

4

Question 7

A hospital records the blood pressure of 50 patients. The mean systolic blood pressure is 120 mmHg with a standard deviation of 10 mmHg. What is the z-score for a patient with a systolic blood pressure of 140 mmHg?

Accepted Answer

$$z = \frac{140 - 120}{10} = 2$$

Question 8

Which of the following is NOT part of the 5-number summary used in a box & whiskers plot?

Accepted Answer

Mean

Question 9

A data set has a mean of 50 and a standard deviation of 5. According to the Empirical Rule, approximately what percentage of data falls within the interval $$[45, 55]$$?

Accepted Answer

68%

Question 10

A frequency distribution table shows the number of students scoring in different ranges on a math test. What does the cumulative frequency for the interval 70-79 represent?

Accepted Answer

The total number of students who scored up to and including 79.

Question 11

A stem & leaf plot is most useful for:

Accepted Answer

Showing the shape of a quantitative data set and retaining original values.

Question 12

A researcher measures the heights of plants in centimeters. Which type of variable is 'height'?

Accepted Answer

Quantitative, continuous

Question 13

Which formula is used to calculate the variance of a sample?

Accepted Answer

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

Question 14

A data set has values: 10, 12, 14, 16, 18. What is the range?

Accepted Answer

$$18 - 10 = 8$$

Question 15

A company wants to know the average salary of its employees. They survey 20 randomly selected employees. Which term best describes the average salary calculated from these 20 employees?

Accepted Answer

Statistic

Question 16

If a data set is skewed to the right, which measure of central tendency is most likely to be greater than the others?

Accepted Answer

Mean

Question 17

A student scores 1.5 standard deviations above the mean on a standardized test. If the mean is 100 and the standard deviation is 20, what is the student's score?

Accepted Answer

$$100 + (1.5 	imes 20) = 130$$

Question 18

Which of the following best describes a qualitative variable?

Accepted Answer

A variable that describes a category or attribute.

Question 19

A frequency distribution has the following frequencies for test scores: 5, 8, 12, 10, 5. What is the relative frequency for the interval with frequency 12?

Accepted Answer

$$\frac{12}{40} = 0.3$$

Question 20

A researcher wants to summarize the spread of a data set. Which measure is most affected by extreme values?

Accepted Answer

Range

Introductory Statistics: Study Guide for Test 1 (Chapters 1–3)

Guida di studio - Domande di pratica

Study guide - Flashcard