Q: If a data set has a mean of $$30$$ and a standard deviation of $$5$$, according to the range rule of thumb, what values are considered 'usual'?

Values between $$30 \pm 2 \times 5$$

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 summary of a sample.

Question 2

A researcher wants to estimate the average height of adult males in a city. She divides the city into neighborhoods and randomly selects several neighborhoods, then measures the height of every adult male in those neighborhoods. Which sampling method is she using?

Accepted Answer

Cluster sampling

Question 3

Which level of measurement allows meaningful ratios and has a true zero point?

Accepted Answer

Ratio

Question 4

A pharmaceutical company conducts an experiment where neither the participants nor the researchers know who receives the actual drug or the placebo. What is this procedure called?

Accepted Answer

Double-blind

Question 5

Which of the following is most resistant to extreme values (outliers) in a data set?

Accepted Answer

Median

Question 6

Given the following data set: 2, 4, 6, 8, 100. Which measure of center is most affected by the outlier?

Accepted Answer

Mean

Question 7

A survey is sent by email to a random sample of university students, but only 40% respond. Which type of bias is most likely present?

Accepted Answer

Nonresponse bias

Question 8

In a normal distribution, approximately what percentage of data falls within two standard deviations of the mean?

Accepted Answer

95%

Question 9

Which formula correctly calculates the sample variance $$s^2$$ for a sample of $$n$$ values $$x_1$$, $$x_2$$, ..., x_n$$ with sample mean $$\bar{x}$$?

Accepted Answer

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

Question 10

A data set has $$Q_1 = 20$, Q_3$ = 40. $$What is the interquartile range (IQR)?

Accepted Answer

$$IQR = 20$$

Question 11

A value $$x in a $$data set has a mean $$\mu = 50$$ and standard deviation $$\sigma = 10. If$$ $$x = 70$$, what is the $$z-$$score?

Accepted Answer

$$z = 2$$

Question 12

Which of the following best describes a lurking variable?

Accepted Answer

A variable that influences both the explanatory and response variables but is not measured.

Question 13

A frequency table for exam scores is constructed with class intervals of 10 points. If the lowest score is 45 and the highest is 95, what is the minimum number of classes needed?

Accepted Answer

5

Question 14

Which graphical method is most appropriate for displaying the distribution of a categorical variable such as favorite color?

Accepted Answer

Bar graph

Question 15

A boxplot shows the median near the lower edge of the box and a long whisker extending to the right. What does this indicate about the distribution?

Accepted Answer

The distribution is skewed right.

Question 16

Which of the following is NOT a source of response bias?

Accepted Answer

Random sampling

Question 17

A researcher wants to compare the effectiveness of two teaching methods. She pairs students based on their prior test scores and randomly assigns one method to each student in the pair. What experimental design is this?

Accepted Answer

Matched-pairs design

Question 18

If a data set has a mean of $$30$$ and a standard deviation of $$5$$, according to the range rule of thumb, what values are considered 'usual'?

Accepted Answer

Values between $$30 \pm 2 	imes 5$$

Question 19

Which formula gives the lower fence for outlier detection using quartiles?

Accepted Answer

$$Q_1 - 1.5$$ 	imes IQR$$

Statistical Foundations and Data Analysis: Mini-Textbook Study Notes

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