Question 1

Which of the following best describes the relationship shown in a scatterplot where, as the number of children per woman increases, the life expectancy decreases?

Accepted Answer

A negative linear relationship

Question 2

Given the data set: 7, 9, 10, 12, 13, 15, 18, what is the sample mean $$\bar{x}$$?

Accepted Answer

$$\bar{x} = \frac{7+9+10+12+13+15+18}{7} = 12$$

Question 3

Which measure of central tendency is most appropriate to use when a data set contains extreme outliers?

Accepted Answer

Median

Question 4

A histogram of annual household incomes is highly right-skewed. Which transformation would make the data easier to model?

Accepted Answer

Logarithmic transformation

Question 5

If a data set has a mean of 56 and a median of 45, what can you infer about the shape of the distribution?

Accepted Answer

The distribution is right-skewed

Question 6

Which of the following is NOT a robust statistic?

Accepted Answer

Mean

Question 7

Given the following five-number summary for test scores: Min = 22, Q1 = 57, Median = 68, Q3 = 74, Max = 95. What is the interquartile range (IQR)?

Accepted Answer

$$IQR = Q_3$ - Q_1$ = 74 - 57 = 17$$

Question 8

A box plot shows the median closer to the lower quartile (Q1) than the upper quartile (Q3). What does this indicate about the data?

Accepted Answer

The data is right-skewed

Question 9

Which formula correctly calculates the sample variance $$s^2$$ for a data set with $$n$$ observations?

Accepted Answer

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

Question 10

In the malaria vaccine case study, what is the explanatory variable?

Accepted Answer

Type of treatment received (PfSPZ vaccine or placebo)

Question 11

A simulation study is used in the malaria vaccine case to:

Accepted Answer

Imitate what might happen if the null hypothesis is true

Question 12

Which of the following best describes a contingency table?

Accepted Answer

A table that summarizes data for two categorical variables

Question 13

If the observed difference in infection rates between two groups is very unlikely to occur by chance alone, what statistical conclusion is most appropriate?

Accepted Answer

Reject the null hypothesis and conclude there is evidence of an effect

Question 14

Which graphical method is most appropriate for visualizing the distribution of a single categorical variable?

Accepted Answer

Bar plot

Question 15

A data set has the following values: 2, 4, 6, 8, 100. Which measure of spread is most affected by the value 100?

Accepted Answer

Standard deviation

Question 16

Which of the following is a disadvantage of using the range as a measure of variability?

Accepted Answer

It is influenced by extreme values

Question 17

A mosaic plot is most useful for visualizing:

Accepted Answer

The relationship between two categorical variables

Question 18

Which of the following formulas is used to calculate the relative frequency of a class?

Accepted Answer

$$	ext{Relative frequency} = \frac{	ext{Frequency of class}}{n}$$

Question 19

Which of the following best describes a unimodal distribution?

Accepted Answer

A distribution with a single prominent peak

Question 20

If a box plot shows several points above the upper whisker, what does this indicate?

Accepted Answer

There are outliers in the data

Summarizing Data: Statistical Measures and Applications in Human Biology

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